Matrix and layer compositions for protection of bioactives

ABSTRACT

The invention relates to matrix and layer compositions comprising a first polymer. The matrix and layer compositions are useful in the delivery of bioactives. In particular, the matrices and layers may have advantageous properties including mechanical properties and protection of bioactives and may also provide for pH-dependent release of a bioactive.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/133,448, filed Apr. 20, 2016, which is acontinuation application of U.S. patent application Ser. No. 14/413,540(now U.S. Pat. No. 9,452,143), filed Jan. 8, 2015, which is a U.S.National Stage Application of PCT International Application No.PCT/US2013/050051, filed Jul. 11, 2013, which claims the benefit ofpriority of U.S. Provisional Application Ser. No. 61/670,817, filed Jul.12, 2012, the disclosure of each is hereby incorporated by reference inits entirety.

FIELD OF THE INVENTION

The invention relates to matrix and layer compositions. The matrix andlayer compositions are useful in the delivery and protection ofbioactives.

BACKGROUND OF THE INVENTION

Supplementing human and animal diets with essential amino acids and/orother bioactive agents improves health and performance. Bioactives maybe sensitive to degradation, yet need to be provided with a particularrelease profile. Combining the bioactive in a particular matrixcomposition or with a layer coating composition comprising a polymer isone way to deliver protected bioactives with a desired release profile.Providing amino acids and/or bioactive agents to ruminants, inparticular, is challenging because microbes in the rumen may digest anddegrade the bioactive agent of interest before it can be absorbed andutilized by the animal. Over the years, various protection approacheshave been taken, but with mixed results. What is needed, therefore, isan improved means for protecting bioactive agents. In particular,compositions that provide pH-dependent release provide advantages in thedelivery of bioactives.

SUMMARY OF THE INVENTION

In one aspect of the present disclosure, a composition comprising alayer formed over a core is provided. The core comprises a bioactiveagent and the layer comprises a first polymer comprising a repeat unitof Formula (I):

-   -   wherein,        -   R², R⁴, and R⁵ are independently hydrogen, hydrocarbyl, or            substituted hydrocarbyl;        -   R⁶ is hydrogen, hydrocarbyl, or substituted hydrocarbyl;        -   R⁷ is optionally present, when present it is hydrogen,            hydrocarbyl, or substituted hydrocarbyl;        -   Z is sulfur, sulfone, sulfoxide, or selenium;        -   n is an integer ≥1; and        -   m is an integer >1.

In another aspect of the present disclosure, an agglomerated compositioncomprising a plurality of bioactives embedded in a matrix is provided.The matrix comprises a first polymer comprising a repeat unit of Formula(I):

-   -   wherein,        -   R², R⁴, and R⁵ are independently hydrogen, hydrocarbyl, or            substituted hydrocarbyl;        -   R⁶ is hydrogen, hydrocarbyl, or substituted hydrocarbyl;        -   R⁷ is optionally present, when present it is hydrogen,            hydrocarbyl, or substituted hydrocarbyl;        -   Z is sulfur, sulfone, sulfoxide, or selenium;        -   n is an integer ≥1; and        -   m is an integer >1.

Other iterations of the disclosure are provided in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application with color drawing(s)will be provided by the Office by request and payment of the necessaryfee.

FIGS. 1A-E document pH-dependent release of2-hydroxy-4-methylthiobutanoic acid (HMTBa) from various preparations ofcoated particles, which are described in Tables 1 and 2. Shown is therelease at pH 2.5 or 6.5 as a function of time. FIG. 1A shows releasefrom prototype 1. FIG. 1B presents release from prototype 2. FIG. 1Cshows release from prototypes 3 and 4. FIG. 1D presents release fromprototype 5. FIG. 1E shows release from prototypes 6 and 7.

FIGS. 2A-B illustrate in situ degradation of the coated particles whosecompositions are described in Tables 1 and 2. FIG. 2A presents thepercentage of dry matter remaining as a function of time in the rumen.FIG. 2B presents the percentage of dry matter remaining at 24 hours foreach sample.

FIG. 3 shows in vitro release of HMTBa at pH 2.5 and 6.5 from anagglomerated matrix preparation.

FIG. 4 presents in vitro release of HMTBa from the indicatedformulations as a function of pH and time. Samples were incubated at pH6.5 from time 0 to hour 16, pH 2.5 from hour 16 to hour 18, and pH 6.5from hour 18 to hour 40.

FIG. 5 documents release from coated particles in a simulated in vitrobag test. The composition of the coated particles is detailed in Table6. Shown is the percent of HMTBa released as a function of pH.

FIG. 6 presents the in vitro release kinetics at pH 2.5 of the coatedparticles detailed in Table 6. Shown is the percent of HMTBa releasedover time.

FIG. 7 shows the physical resilience of the coated particles detailed inTable 7 and a reference formulation. Plotted is the percent of HMTBa orD,L-methionine released after the indicated number of weight impacts.

FIG. 8 presents release from the coated particles detailed in Table 7and a reference formulation in a simulated in situ bag test. Plotted isthe percent of HMTBa or D,L-methionine released as a function of pH.

FIG. 9 shows the in vitro release kinetics at pH 2.5 of the coatedparticles detailed in Table 7 and a reference formulation. Shown is thepercent of HMTBa or D,L-methionine released over time.

DETAILED DESCRIPTION OF THE INVENTION

I. Composition Comprising a Layer Formed Over a Core

The present disclosure provides a composition comprising a layer formedover a core. As described in further detail herein, the layer comprisesa first polymer having a repeat unit of Formula (I) and the corecomprises a bioactive.

(a). Layer

The layer of the composition comprises a first polymer. The firstpolymer comprises a repeat unit of Formula (I):

-   -   wherein,        -   R², R⁴, and R⁵ are independently chosen from hydrogen,            hydrocarbyl, and substituted hydrocarbyl;        -   R⁶ is chosen from hydrogen, hydrocarbyl, and substituted            hydrocarbyl;        -   R⁷ is optionally present, when present it is chosen from            hydrogen, hydrocarbyl, and substituted hydrocarbyl;        -   Z is chosen from sulfur, sulfone, sulfoxide, and selenium;        -   n is an integer ≥1; and        -   m is an integer >1.

In some embodiments, R² may be chosen from hydrocarbyl, substitutedhydrocarbyl, and hydrogen. In some embodiments, R² may be a lower chainalkyl groups including methyl, ethyl, propyl, butyl, pentyl, and hexyl.In another embodiment, R² may be phenyl, benzyl, or substituted phenylor benzyl. In preferred embodiments, R² may be hydrogen.

R⁴ and R⁵ are independently chosen from hydrogen, hydrocarbyl, andsubstituted hydrocarbyl. The —(CR⁴R⁵)_(n)— may constitute a hydrocarbylchain which may be linear or branched, with n representing the number oflinked carbon atoms in the chain. In various embodiments, n may be equalto or greater than 1. In some embodiments, n may range from 1 to 20 andthe hydrocarbyl chain comprises from 1 to 20 linked carbon atoms. In oneembodiment, n may range from 1 to 5. In still another embodiment, n maybe equal to 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,19, or 20. R⁴ and R⁵ may be hydrogen throughout the chain, in otheraspects select R⁴ and R⁵ may be hydrocarbyl or substituted hydrocarbyl.

Formula (I) also contains a heteroatom Z group. In some embodiments, theZ may be selenium, sulfur, sulfoxide, or sulfone groups. The selenium,or sulfur atoms may be charged and/or be present in various oxidationstates within the molecule. Where the Z carries a charge, thecomposition may further comprise a counterion including, but not limitedto lithium, sodium, potassium, calcium, magnesium, and the like.

R⁶ in Formula (I) may be chosen from hydrogen, hydrocarbyl, andsubstituted hydrocarbyl. Where R⁶ is a hydrocarbyl, it may be any alkylchain but is preferably a lower chain alkyl group such as methyl, ethyl,propyl, butyl, pentyl, or hexyl. The lower alkyl groups may additionallybe branched or cyclic. Non-limiting examples include isopropyl,isobutyl, sec-butyl, t-butyl, cyclopropyl, cyclobutyl, cyclopentyl, andthe like. In another embodiment, R⁶ may be phenyl, benzyl, orsubstituted phenyl or benzyl. In an exemplary embodiment, R⁶ may bemethyl.

R⁷ may be optionally present in the repeat unit comprising Formula (I).When present R⁷, is chosen from hydrocarbyl, substituted hydrocarbyl,and hydrogen. Where R⁷ is a hydrocarbyl, it may be any alkyl group butis preferably a lower chain alkyl group such as methyl, ethyl, propyl,butyl, pentyl, or hexyl. The lower alkyl groups may additionally bebranched or cyclic, non-limiting examples include isopropyl, isobutyl,sec-butyl, t-butyl, cyclopropyl, cyclobutyl, cyclopentyl, and the like.In another embodiment, R⁷ may be phenyl, benzyl, or substituted phenylor benzyl. In a further embodiment, R⁷ may be hydrogen.

The molecular weight of the first polymer can and will vary in differentembodiments. The variable m represents the number of repeat units in thepolymer. Generally, m is greater than 1. In one embodiment, m is greaterthan 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or20. In other embodiments, m may be greater than 20. In particularembodiments, m ranges from 2 to 10.

In some embodiments, the molecular weight of the first polymer may be atleast 500 Da, or at least 600 Da, or at least 700 Da, or at least 800Da, or at least 900 Da, or at least 1,000 Da, or at least 1,100 Da, orat least 1,200 Da, or at least 1,300 Da, or at least 1,400 Da, or atleast 1,500 Da, or at least 1,600 Da, or at least 1,700 Da, or at least1,800 Da, or at least 1,900 Da, or at least 2,000 Da. In another aspect,the molecular weight of the polymer may range from 800 Da to about10,000 Da, or from about 2,000 Da to about 5,000 Da, or from about 2,000Da to about 10,000 Da. In a further embodiment, the molecular weight ofthe polymer may be greater than about 10,000 Da. The weight of a mixtureof polymers may be characterized by its weight-average molecular weight.In some aspects, the weight-average molecular weight of the polymers maybe at least 500 Da, or at least 600 Da, or at least 700 Da, or at least800 Da, or at least 900 Da, or at least 1,000 Da, or at least 1,100 Da,or at least 1,200 Da, or at least 1,300 Da, or at least 1,400 Da, or atleast 1,500 Da, or at least 1,600 Da, or at least 1,700 Da, or at least1,800 Da, or at least 1,900 Da, or at least 2,000 Da. In other aspects,the weight-average molecular weight may be about 2,000 Da, about 3,000Da, about 4,000 Da, or about 5,000 Da. The molecular weight may bedetermined by gel permeation chromatography or other means known in theart.

In certain embodiments, the first polymer may also be characterized by amonomer percent. A monomer percent is the percent of the polymercomposition which is monomeric. In some aspects, the monomer percent isless than 20%. In other aspects, the monomer percent is less than 15%.More preferably, the monomer percent is less than 10%. In variousaspects, the monomer percent is less than 9%, less than 8%, less than7%, less than 6%, less than 5%, less than 4%, less than 3%, less than2%, or less than 1%.

In one preferred embodiment, the first polymer comprises a repeat unitcomprising Formula (II):

-   -   wherein, R², R⁶, R⁷, Z, n, and m are as defined for Formula (I).

In another alternative embodiment, the first polymer comprises a repeatunit comprising Formula (IIa):

-   -   wherein, R⁶, R⁷, and m are as defined for Formula (I) and Z is        selected from sulfur, sulfone, sulfoxide, and selenium.

In another exemplary embodiment, the first polymer comprises a repeatunit comprising Formula (III):

-   -   wherein, m is as defined for Formula (I).

In some aspects of the invention, the first polymer may have chiralcenters. In particular, the carbon alpha to the carbonyl unit in thecompound of Formula (I), (II), or (Ill) may be chiral and may have an Ror an S configuration. In some embodiments, the configuration at thisposition may be R. In other embodiments, the configuration at thisposition may be S. In various aspects, the repeat units may be all R,all S, or comprise a combination of R and S repeat units, for example,the configuration of the repeat units may alternate in block orrandomly.

The layer comprising the first polymer may comprise at least oneadditional agent. The additional agent may be chosen from polymers,including crystalline and semi-crystalline polymers. Examples ofsuitable polymers, without limitation, are polymers of acrylates,aminoacrylates, alkylene succinates, alkylene oxalates, amides, aminoacids, anhydrides, arylates, carbonates, cellulose (including, but notlimited to, hydroxymethylcellulose, hydroxyproplycellulose,methylcellulose, carboxymethyl cellulose and ethylcellulose),caprolactone, cyanoacrylates, dihydropyrans, dioxanes, dioxanones, etherether ketones, ethylene glycol, fumarates, hydroxyalkanoates,hydroxyl-esters, imides, ketals, lactides, methacrylates, methylolefins, orthoesters, phosphazines, styrenes, terephthalates,trimethylene carbonate, urathanes, vinyl acetates, vinyl ketones, vinylhalides, derivatives, isomers, and mixtures thereof. The additionalagent may also be a wax, including natural and synthetic waxes; fattyacids, including C₁₂-C₃₀ fatty acids, and fatty acid esters, includingmonogylcerides, diglycerides, and triglycerides. Non-limiting examplesinclude canola oil, coconut oil, corn oil, cottonseed oil, lauric acid,linoleic acid, oleic acid, palm oil, palmitic acid, soy oil, soybeanoil, stearic acid, stearin, sunflower seed oil, vegetable oil, andcombinations thereof. The oils may be hydrogenated, non-hydrogenated, orpartially hydrogenated. The additional agent may be a flow agent,including carbonates and talcs and combinations thereof. Carbonates maybe selected from copper carbonate, zinc carbonate, calcium carbonate,magnesium carbonate, potassium carbonate, sodium carbonate, andcombinations thereof.

In one embodiment, the additional agent is a pH-sensitive polymer andmay be chosen from natural and modified polymers (e.g. chitosan)including blends with monomers. The additional agents may be amino typepolymers. Amino type polymers include, but are not limited to, pyridine,pyridine derivatives, amino acrylate type monomers, such as dialkylaminoethyl acrylate, styrene, styrene derivatives (such aspoly-2-vinylpyridine-co-styrene), acrylonitrile, acrylate type monomersof acrylic acid, vinyl esters, vinyl acetate, and vinyl substitutedheterocyclic rings that contain nitrogen fusions (such as vinylcarbazole, vinyl quinolone and N-vinylpyrrole). In one preferredembodiment, the additional agent is poly-2-vinylpyridine-co-styrene.

In one alternative embodiment, the layer composition is free ofethylcellulose.

In some embodiments, the first polymer comprises 100% of the layer. Inother embodiments, the first polymer is about 5% to about 50% by weightof the layer and the additional agent comprises from about 50% to about95% by weight of the layer. In various embodiments, the additional agentcomprises about 50%, 60%, 70%, 80%, or 90% of the layer. In embodimentswhere two or more additional agents are provided in the layer, eachagent may be provided in any ratio without limitation.

The total weight percentage of the layer can and will vary. In someembodiments, the layer ranges from about 1% to about 50% by weight ofthe total composition. More preferably, the layer ranges from about 5%to about 15% by weight, or from about 8% to about 12% by weight. In someembodiments, the total weight percentage of the layer less than about1%, less than about 2%, less than about 3%, less than about 4%, lessthan about 5%, less than about 6%, less than about 7%, less than about8%, less than about 9%, less than about 10%, less than about 11%, lessthan about 12%, less than about 13%, less than about 14% or less thanabout 15% by weight.

(b). Core

The composition further comprises a core comprising a bioactive. In someembodiments, the core contains one bioactive. In other embodiments, thecore contains more than one bioactive. When more than one bioactive ispresent in the core, they can be provided in any ratio. For example,when two bioactives are present they can be present in a ratio of about99:1, 95:5, 90:10, 85:15, 80:20, 75:25, 70:30, 65:35, 60:40, 55:45, or50:50 by weight percent, or at any ratio between the listed ratios. Whenmore than two bioactives are present, they may similarly be present inany ratio without limitation.

The bioactive can be present in the core composition in a weight ofabout 20% to about 90% of the total composition. In some embodiments thebioactive is about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about65%, about 70%, about 80%, about 90%, or about 99% by weight of thetotal composition. In a preferred embodiment, the bioactive is presentin an amount of about 80% to about 90%, or 85% to about 95%, or about95% to about 99% by weight of the total composition.

i. Bioactive

The bioactive may be chosen from any biologically relevant molecule.Non-limiting examples of bioactives include vitamins, minerals (e.g.,organic or inorganic), antioxidants, organic acids, poly unsaturatedfatty acid (“PUFA”)s, essential oils, pharmaceutically active agents,amino acids or amino acid analogues, enzymes, prebiotics, probiotics,herbs, and pigments.

Suitable vitamins include vitamin C, vitamin A, vitamin E, vitamin B12,vitamin K, riboflavin, niacin, vitamin D, vitamin B6, folic acid,pyridoxine, thiamine, pantothenic acid, and biotin. The form of thevitamin may include salts of the vitamin, derivatives of the vitamin,compounds having the same or similar activity of a vitamin, andmetabolites of a vitamin.

Suitable organic trace mineral may comprise a metal chelate comprisingmetal ions and an amino acid ligand. Alternatively, the organic tracemineral may be a metal salt comprising metal ions and an amino acidanion. The metal ions may be selected from the group consisting of zincions, copper ions, manganese ions, iron ions, chromium ions, cobaltions, magnesium ions, calcium ions, and combinations thereof. The aminoacids may be selected from the group comprising alanine, arginine,asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine,histidine, isoleucine, leucine, lysine, methionine, phenylalanine,proline, serine, threonine, tryptophan, tyrosine, and valine, or theirhydroxy analogs. In certain embodiments, the copper and zinc ions arepreferably divalent, i.e., each ion carries a charge of 2⁺. The molarratio of amino acids to metal ions in the chelate molecule may generallyvary from 1:1 to 3:1 or higher. Typically, a metal chelate may comprisea mixture of 1:1, 2:1, and 3:1 species. Preferably, the molar ratio ofamino acids to metal ion in the chelate molecule may generally vary from1.5:1 to 2.5:1. In an aqueous medium, the relative proportions of thesespecies are determined by the applicable stability constants. Where thenumber of ligands equates to the charge on the metal ion, the charge istypically balanced because the carboxyl moieties of the amino acids arein deprotonated form. For example, in the chelate species wherein themetal cation carries a charge of 2+ and the amino acid to metal ratio is2:1, each of the hydroxy or amino groups is understood to be bound by acoordinate covalent bond to the metal ion. Where the number of ligandsexceeds the charge on the metal ion, e.g., in a 3:1 chelate of adivalent metal ion, the amino acids in excess of the charge typicallymay remain in a protonated state to balance the charge. On the otherhand, where the positive charge on the metal ion exceeds the number ofamino acids, the charge may be balanced by the presence of another anionsuch as, for example, chloride, bromide, iodide, bicarbonate, hydrogensulfate, dihydrogen phosphate and combinations thereof. Divalent anionsmay also be present. In an exemplary embodiment, the metal chelatecomprises 2-hydroxy-4-methylthiobutanoic acid (HMTBa).

The mineral may be an inorganic trace mineral. Suitable inorganic traceminerals include, for example, metal sulfates, metal oxides, metalhydroxides, metal oxychlorides, metal carbonates, and metal halides. Byway of non-limiting example, the inorganic trace mineral may be coppersulfate, copper oxide, copper chloride, or copper carbonate.Alternatively, the inorganic trace mineral may be manganese sulfate,manganese chloride, or manganous oxide. In another embodiment, theinorganic trace mineral may be zinc sulfate, zinc oxide, zinc chloride,or zinc carbonate. In yet an additional embodiment, the inorganic tracemineral may be sodium selenite or sodium selenate.

Suitable antioxidants include, but are not limited to, ascorbic acid andits salts, ascorbyl palmitate, ascorbyl stearate, anoxomer,n-acetylcysteine, benzyl isothiocyanate, m-aminobenzoic acid,o-aminobenzoic acid, p-aminobenzoic acid (PABA), butylatedhydroxyanisole (BHA), butylated hydroxytoluene (BHT), caffeic acid,canthaxantin, alpha-carotene, beta-carotene, beta-caraotene,beta-apo-carotenoic acid, carnosol, carvacrol, catechins, cetyl gallate,chlorogenic acid, citric acid and its salts, clove extract, coffee beanextract, p-coumaric acid, 3,4-dihydroxybenzoic acid,N,N′-diphenyl-p-phenylenediamine (DPPD), dilauryl thiodipropionate,distearyl thiodipropionate, 2,6-di-tert-butylphenol, dodecyl gallate,edetic acid, ellagic acid, erythorbic acid, sodium erythorbate,esculetin, esculin, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline(ethoxyquin), ethyl gallate, ethyl maltol, ethylenediaminetetraaceticacid (EDTA), eucalyptus extract, eugenol, ferulic acid, flavonoids(e.g., catechin, epicatechin, epicatechin gallate, epigallocatechin(EGC), epigallocatechin gallate (EGCG), polyphenolepigallocatechin-3-gallate, flavones (e.g., apigenin, chrysin,luteolin), flavonols (e.g., datiscetin, myricetin, daemfero),flavanones, fraxetin, fumaric acid, gallic acid, gentian extract,gluconic acid, glycine, gum guaiacum, hesperetin, alpha-hydroxybenzylphosphinic acid, hydroxycinammic acid, hydroxyglutaric acid,hydroquinone, n-hydroxysuccinic acid, hydroxytryrosol, hydroxyurea, ricebran extract, lactic acid and its salts, lecithin, lecithin citrate;R-alpha-lipoic acid, lutein, lycopene, malic acid, maltol, 5-methoxytryptamine, methyl gallate, monoglyceride citrate; monoisopropylcitrate; morin, beta-naphthoflavone, nordihydroguaiaretic acid (NDGA),octyl gallate, oxalic acid, palmityl citrate, phenothiazine,phosphatidylcholine, phosphoric acid, phosphates, phytic acid,phytylubichromel, pimento extract, propyl gallate, polyphosphates,quercetin, trans-resveratrol, rosemary extract, rosmarinic acid, sageextract, sesamol, silymarin, sinapic acid, succinic acid, stearylcitrate, syringic acid, tartaric acid, thymol, tocopherols (i.e.,alpha-, beta-, gamma- and delta-tocopherol), tocotrienols (i.e., alpha-,beta-, gamma- and delta-tocotrienols), tyrosol, vanilic acid,2,6-di-tert-butyl-4-hydroxymethylphenol (i.e., lonox 100),2,4-(tris-3′,5′-bi-tert-butyl-4′-hydroxybenzyl)-mesitylene (i.e., lonox330), 2,4,5-trihydroxybutyrophenone, ubiquinone, tertiary butylhydroquinone (TBHQ), thiodipropionic acid, trihydroxy butyrophenone,tryptamine, tyramine, uric acid, vitamin K and derivates, vitamin Q10,wheat germ oil, zeaxanthin, or combinations thereof.

A variety of organic acids comprised of carboxylic acids are suitable.In one embodiment, the organic acid may contain from about one to abouttwenty-five carbon atoms. In another embodiment, the organic acid mayhave from about three to about twenty-two carbon atoms. In a furtherembodiment, the organic acid may contain from about three to abouttwelve carbon atoms. In yet another embodiment, the organic acid maycontain from about eight to about twelve carbon atoms. In still anotherembodiment, the organic acid may contain from about two to about sixcarbon atoms. Suitable organic acids, by way of non-limiting example,include formic acid, acetic acid, propionic acid, butanoic acid, benzoicacid, lactic acid, malic acid, tartaric acid, mandelic acid, citricacid, fumaric acid, sorbic acid, boric acid, succinic acid, adipic acid,glycolic acid, cinnamaldehyde, and glutaric acid.

Salts of organic acids comprising carboxylic acids are also suitable forcertain embodiments. Representative suitable salts include the ammonium,magnesium, calcium, lithium, sodium, potassium, selenium, iron, copper,and zinc salts of organic acids. In one embodiment, the organic acid isan ammonium, magnesium, calcium, lithium, sodium, potassium, selenium,iron, copper, or zinc salt of formic acid. In another embodiment, theorganic acid is an ammonium, magnesium, calcium, lithium, sodium,potassium, selenium, iron, copper, or zinc salt of acetic acid. In yetanother embodiment, the organic acid is an ammonium, magnesium, calcium,lithium, sodium, potassium, selenium, iron, copper, or zinc salt ofpropionic acid. In an additional embodiment, the organic acid is anammonium, magnesium, calcium, lithium, sodium, potassium, selenium,iron, copper, or zinc salt of butanoic acid. In a further embodiment,the organic acid is an ammonium, magnesium, calcium, lithium, sodium,potassium, selenium, iron, copper, or zinc salt of benzoic acid. Instill another embodiment, the organic acid is an ammonium, magnesium,calcium, lithium, sodium, potassium, selenium, iron, copper, or zincsalt of lactic acid. In yet another embodiment, the organic acid is anammonium, magnesium, calcium, lithium, sodium, potassium, selenium,iron, copper, or zinc salt of malic acid. In still another embodiment,the organic acid is an ammonium, magnesium, calcium, lithium, sodium,potassium, selenium, iron, copper, or zinc salt of tartaric acid. In afurther embodiment, the organic acid is an ammonium, magnesium, calcium,lithium, sodium, potassium, selenium, iron, copper, or zinc salt ofmandelic acid. In yet another embodiment, the organic acid is anammonium, magnesium, calcium, lithium, sodium, potassium, selenium,iron, copper, or zinc salt of citric acid. In an additional embodiment,the organic acid is an ammonium, magnesium, calcium, lithium, sodium,potassium, selenium, iron, copper, or zinc salt of fumaric acid. In anadditional embodiment, the organic acid is an ammonium, magnesium,calcium, lithium, sodium, potassium, selenium, iron, copper, or zincsalt of sorbic acid. In another embodiment, the organic acid is anammonium, magnesium, calcium, lithium, sodium, potassium, selenium,iron, copper, or zinc salt of boric acid. In yet another embodiment, theorganic acid is an ammonium, magnesium, calcium, lithium, sodium,potassium, selenium, iron, copper, or zinc salt of succinic acid. Inanother embodiment, the organic acid is an ammonium, magnesium, calcium,lithium, sodium, potassium, selenium, iron, copper, or zinc salt ofadipic acid. In yet another embodiment, the organic acid is an ammonium,magnesium, calcium, lithium, sodium, potassium, selenium, iron, copper,or zinc salt of glycolic acid. In an additional embodiment, the organicacid is an ammonium, magnesium, calcium, lithium, sodium, potassium,selenium, iron, copper, or zinc salt of glutaric acid.

Alternatively, the organic acid may be comprised of a substitutedcarboxylic acid. A substituted carboxylic acid generally has the samefeatures as those detailed above for carboxylic acids, but thehydrocarbyl chain has been modified such that it is branched, is part ofa ring structure, or contains some other substitution. In oneembodiment, the substituted carboxylic acid may contain one or moreadditional carboxyl groups. Saturated dicarboxylic acids include malonicacid, succinic acid, glutaric acid, and adipic acid, and unsaturateddicarboxylic acids include maleic acid and fumaric acid. In anotherembodiment, the substituted carboxylic acid may contain one or morehydroxy groups. A substituted carboxylic acid with a hydroxy group onthe alpha carbon, i.e., the carbon adjacent to the carboxyl carbon, isgenerally called a α-hydroxy carboxylic acid. Examples of suitableα-hydroxy carboxylic acids include glycolic acid, lactic acid, malicacid, and tartaric acid. In an alternate embodiment, the substitutedcarboxylic acid may contain one or more carbonyl groups. In yet anotherembodiment, the substituted carboxylic acid may contain an amino groupon the alpha carbon, i.e., is an α-amino acid. In one embodiment, theα-amino acid may be one of the twenty standard amino acids orderivatives thereof. In another embodiment, the α-amino acid may be anessential α-amino acid selected from the group consisting of arginine,histidine, isoleucine, leucine, lysine, methionine, phenylalanine,threonine, tryptophan, and valine. Salts of organic acids comprisingsubstituted carboxylic acids are also suitable for certain embodiments.Representative suitable salts include the ammonium, magnesium, calcium,lithium, sodium, potassium, selenium, iron, copper, and zinc salts oforganic acids comprising substituted carboxylic acids.

Suitable PUFAs include a long chain fatty acid with at least 18 carbonatoms and at least two carbon-carbon double bonds, generally in thecis-configuration. In an exemplary embodiment, the PUFA is an omegafatty acid. The PUFA may be an omega-3 fatty acid in which the firstdouble bond occurs in the third carbon-carbon bond from the methyl endof the carbon chain (i.e., opposite the carboxyl acid group). Suitableexamples of omega-3 fatty acids include all-cis 7,10,13-hexadecatrienoicacid; all-cis-9,12,15-octadecatrienoic acid (alpha-linolenic acid, ALA);all-cis-6,9,12,15,-octadecatetraenoic acid (stearidonic acid);all-cis-8,11,14,17-eicosatetraenoic acid (eicosatetraenoic acid);all-cis-5,8,11,14,17-eicosapentaenoic acid (eicosapentaenoic acid, EPA);all-cis-7,10,13,16,19-docosapentaenoic acid (clupanodonic acid, DPA);all-cis-4,7,10,13,16,19-docosahexaenoic acid (docosahexaenoic acid,DHA); all-cis-4,7,10,13,16,19-docosahexaenoic acid; andall-cis-6,9,12,15,18,21-tetracosenoic acid (nisinic acid). In analternative embodiment, the PUFA may be an omega-6 fatty acid in whichthe first double bond occurs in the sixth carbon-carbon bond from themethyl end of the carbon chain. Examples of omega-6 fatty acids includeall-cis-9,12-octadecadienoic acid (linoleic acid);all-cis-6,9,12-octadecatrienoic acid (gamma-linolenic acid, GLA);all-cis-11,14-eicosadienoic acid (eicosadienoic acid);all-cis-8,11,14-eicosatrienoic acid (dihomo-gamma-linolenic acid, DGLA);all-cis-5,8,11,14-eicosatetraenoic acid (arachidonic acid, AA);all-cis-13,16-docosadienoic acid (docosadienoic acid);all-cis-7,10,13,16-docosatetraenoic acid (adrenic acid); andall-cis-4,7,10,13,16-docosapentaenoic acid (docosapentaenoic acid). Inyet another alternative embodiment, the PUFA may be an omega-9 fattyacid in which the first double bond occurs in the ninth carbon-carbonbond from the methyl end of the carbon chain, or a conjugated fattyacid, in which at least one pair of double bonds are separated by onlyone single bond. Suitable examples of omega-9 fatty acids includecis-9-octadecenoic acid (oleic acid); cis-11-eicosenoic acid (eicosenoicacid); all-cis-5,8,11-eicosatrienoic acid (mead acid); cis-13-docosenoicacid (erucic acid), and cis-15-tetracosenoic acid (nervonic acid).Examples of conjugated fatty acids include 9Z,11E-octadeca-9,11-dienoicacid (rumenic acid); 10E,12Z-octadeca-9,11-dienoic acid;8E,10E,12Z-octadecatrienoic acid (α-calendic acid);8E,10E,12E-octadecatrienoic acid (β-Calendic acid);8E,10Z,12E-octadecatrienoic acid (jacaric acid);9E,11E,13Z-octadeca-9,11,13-trienoic acid (α-eleostearic acid);9E,11E,13E-octadeca-9,11,13-trienoic acid (β-eleostearic acid);9Z,11Z,13E-octadeca-9,11,13-trienoic acid (catalpic acid), and9E,11Z,13E-octadeca-9,11,13-trienoic acid (punicic acid).

Suitable essential oils include, but are not limited to, peppermint oil,cinnamon leaf oil, lemongrass oil, clove oil, castor oil, wintergreenoil, sweet orange, spearmint oil, ceaderwood oil, aldehyde C16,α-terpineol, amyl cinnamic aldehyde, amyl salicylate, anisic aldehyde,benzyl alcohol, benzyl acetate, camphor, capsaicin, cinnamaldehyde,cinnamic alcohol, carvacrol, carveol, citral, citronellal, citronellol,p-cymene, diethyl phthalate, dimethyl salicylate, dipropylene glycol,eucalyptol (cineole), eugenol, iso-eugenol, galaxolide, geraniol,guaiacol, ionone, listea cubea, menthol, menthyl salicylate, methylanthranilate, methyl ionone, methyl salicylate, a-phellandrene,pennyroyal oil, perillaldehyde, 1- or 2-phenyl ethyl alcohol, 1- or2-phenyl ethyl propionate, piperonal, piperonyl acetate, piperonylalcohol, D-pulegone, terpinen-4-ol, terpinyl acetate, 4-tertbutylcyclohexyl acetate, thyme oil, thymol, metabolites oftrans-anethole, vanillin, ethyl vanillin, similar compositions, andcombinations thereof.

Probiotics and prebiotics may include yeast and bacteria that helpestablish an immune protective rumen or gut microflora as well as smalloligosaccharides. By way of non-limiting example, yeast-derivedprobiotics and prebiotics include yeast cell wall derived componentssuch as β-glucans, arabinoxylan isomaltose, agarooligosaccharides,lactosucrose, cyclodextrins, lactose, fructooligosaccharides,laminariheptaose, lactulose, β-galactooligosaccharides,mannanoligosaccharides, raffinose, stachyose, oligofructose, glucosylsucrose, sucrose thermal oligosaccharide, isomalturose, caramel, inulin,and xylooligosaccharides. In an exemplary embodiment, the yeast-derivedagent may be β-glucans and/or mannanoligosaccharides. Sources for yeastcell wall derived components include Saccharomyces bisporus,Saccharomyces boulardii, Saccharomyces cerevisiae, Saccharomycescapsularis, Saccharomyces delbrueckii, Saccharomyces fermentati,Saccharomyces lugwigii, Saccharomyces microellipsoides, Saccharomycespastorianus, Saccharomyces rosei, Candida albicans, Candida cloaceae,Candida tropicalis, Candida utilis, Geotrichum candidum, Hansenulaamericana, Hansenula anomala, Hansenula wingei, and Aspergillus oryzae.

Probiotics and prebiotics may also include bacteria cell wall derivedagents such as peptidoglycan and other components derived fromgram-positive bacteria with a high content of peptidoglycan. Exemplarygram-positive bacteria include Lactobacillus acidophilus, Bifedobactthermophilum, Bifedobat longhum, Streptococcus faecium, Bacilluspumilus, Bacillus subtilis, Bacillus licheniformis, Lactobacillusacidophilus, Lactobacillus casei, Enterococcus faecium, Bifidobacteriumbifidium, Propionibacterium acidipropionici, Propionibacteriiumfreudenreichii, and Bifidobacterium pseudolongum.

The bioactive may be an amino acid or amino acid analogue. Non-limitingsuitable amino acids alanine, arginine, asparagine, aspartic acid,cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine,leucine, lysine, methionine, phenylalanine, proline, serine, threonine,tryptophan, tyrosine, and valine, or other known amino acids. Amino acidanalogs include α-hydroxy analogs, as well side chain protected analogsor N-derivatized amino acids including 2-hydroxy-4-methylthiobutanoicacid or its corresponding salt. In one embodiment, the bioactive is thecalcium salt of 2-hydroxy-4-methylthiobutanoic acid.

The bioactive may also be an enzyme. As used herein, variants areunderstood to be included in the term enzyme. Suitable non-limitingexamples of enzymes include amylases, carbohydrases, cellulases,esterases, galactonases, galactosidases, glucanases, hemicellulases,hydrolases, lipases, oxidoreductases, pectinases, peptidases,phosphatases, phospholipases, phytases, proteases, transferases,xylanases, and combinations thereof.

Suitable herbals and herbal derivatives, as used herein, refer to herbalextracts, and substances derived from plants and plant parts, such asleaves, flowers and roots, without limitation. Non-limiting exemplaryherbals and herbal derivatives include agrimony, alfalfa, aloe vera,amaranth, angelica, anise, barberry, basil, bayberry, bee pollen, birch,bistort, blackberry, black cohosh, black walnut, blessed thistle, bluecohosh, blue vervain, boneset, borage, buchu, buckthorn, bugleweed,burdock, capsicum, cayenne, caraway, cascara sagrada, catnip, celery,centaury, chamomile, chaparral, chickweed, chicory, chinchona, cloves,coltsfoot, comfrey, cornsilk, couch grass, cramp bark, culver's root,cyani, cornflower, damiana, dandelion, devils claw, dong quai,echinacea, elecampane, ephedra, eucalyptus, evening primrose, eyebright,false unicorn, fennel, fenugreek, figwort, flaxseed, garlic, gentian,ginger, ginseng, golden seal, gotu kola, gum weed, hawthorn, hops,horehound, horseradish, horsetail, hoshouwu, hydrangea, hyssop, icelandmoss, irish moss, jojoba, juniper, kelp, lady's slipper, lemon grass,licorice, lobelia, mandrake, marigold, marjoram, marshmallow, mistletoe,mullein, mustard, myrrh, nettle, oatstraw, oregon grape, papaya,parsley, passion flower, peach, pennyroyal, peppermint, periwinkle,plantain, pleurisy root, pokeweed, prickly ash, psyllium, quassia, queenof the meadow, red clover, red raspberry, redmond clay, rhubarb, rosehips, rosemary, rue, safflower, saffron, sage, St. John's wort,sarsaparilla, sassafras, saw palmetto, scullcap, senega, senna,shepherd's purse, slippery elm, spearmint, spikenard, squawvine,stillingia, strawberry, taheebo, thyme, uva ursi, valerian, violet,watercress, white oak bark, white pine bark, wild cherry, wild lettuce,wild yam, willow, wintergreen, witch hazel, wood betony, wormwood,yarrow, yellow dock, yerba santa, yucca and combinations thereof.

Suitable non-limiting pigments include actinioerythrin, alizarin,alloxanthin, β-apo-2′-carotenal, apo-2-lycopenal, apo-6′-lycopenal,astacein, astaxanthin, azafrinaldehyde, aacterioruberin, aixin,α-carotine, β-carotine, γ-carotine, β-carotenone, canthaxanthin,capsanthin, capsorubin, citranaxanthin, citroxanthin, crocetin,crocetinsemialdehyde, crocin, crustaxanthin, cryptocapsin,α-cryptoxanthin, β-cryptoxanthin, cryptomonaxanthin, cynthiaxanthin,decaprenoxanthin, dehydroadonirubin, diadinoxanthin,1,4-diamino-2,3-dihydroanthraquinone, 1,4-dihydroxyanthraquinone,2,2′-Diketospirilloxanthin, eschscholtzxanthin, eschscholtzxanthone,flexixanthin, foliachrome, fucoxanthin, gazaniaxanthin,hexahydrolycopene, hopkinsiaxanthin, hydroxyspheriodenone,isofucoxanthin, loroxanthin, lutein, luteoxanthin, lycopene,lycopersene, lycoxanthin, morindone, mutatoxanthin, neochrome,neoxanthin, nonaprenoxanthin, OH-Chlorobactene, okenone, oscillaxanthin,paracentrone, pectenolone, pectenoxanthin, peridinin, phleixanthophyll,phoeniconone, phoenicopterone, phoenicoxanthin, physalien, phytofluene,pyrrhoxanthininol, quinones, rhodopin, rhodopinal, rhodopinol,rhodovibrin, rhodoxanthin, rubixanthone, saproxanthin,semi-α-carotenone, semi-β-carotenone, sintaxanthin, siphonaxanthin,siphonein, spheroidene, tangeraxanthin, torularhodin, torularhodinmethyl ester, torularhodinaldehyde, torulene,1,2,4-trihydroxyanthraquinone, triphasiaxanthin, trollichrome,vaucheriaxanthin, violaxanthin, wamingone, xanthin, zeaxanthin,α-zeacarotene and combinations thereof.

Suitable non-limiting pharmaceutically acceptable agents include anacid/alkaline-labile drug, a pH dependent drug, or a drug that is a weakacid or a weak base. Examples of acid-labile drugs include statins(e.g., pravastatin, fluvastatin and atorvastatin), antibiotics (e.g.,penicillin G, ampicillin, streptomycin, erythromycin, clarithromycin andazithromycin), nucleoside analogs [e.g., dideoxyinosine (ddl ordidanosine), dideoxyadenosine (ddA), dideoxycytosine (ddC)], salicylates(e.g, aspirin), digoxin, bupropion, pancreatin, midazolam, andmethadone. Drugs that are only soluble at acid pH include nifedipine,emonapride, nicardipine, amosulalol, noscapine, propafenone, quinine,dipyridamole, josamycin, dilevalol, labetalol, enisoprost, andmetronidazole. Drugs that are weak acids include phenobarbital,phenytoin, zidovudine (AZT), salicylates (e.g., aspirin), propionic acidcompounds (e.g., ibuprofen), indole derivatives (e.g., indomethacin),fenamate compounds (e.g., meclofenamic acid), pyrrolealkanoic acidcompounds (e.g., tolmetin), cephalosporins (e.g., cephalothin,cephalaxin, cefazolin, cephradine, cephapirin, cefamandole, andcefoxitin), 6-fluoroquinolones, and prostaglandins. Drugs that are weakbases include adrenergic agents (e.g., ephedrine, desoxyephedrine,phenylephrine, epinephrine, salbutamol, and terbutaline), cholinergicagents (e.g., physostigmine and neostigmine), antispasmodic agents(e.g., atropine, methantheline, and papaverine), curariform agents(e.g., chlorisondamine), tranquilizers and muscle relaxants (e.g.,fluphenazine, thioridazine, trifluoperazine, chlorpromazine, andtriflupromazine), antidepressants (e.g., amitriptyline andnortriptyline), antihistamines (e.g., diphenhydramine, chlorpheniramine,dimenhydrinate, tripelennamine, perphenazine, chlorprophenazine, andchlorprophenpyridamine), cardioactive agents (e.g., verapamil,diltiazem, gallapomil, cinnarizine, propranolol, metoprolol andnadolol), antimalarials (e.g., chloroquine), analgesics (e.g.,propoxyphene and meperidine), antifungal agents (e.g., ketoconazole anditraconazole), antimicrobial agents (e.g., cefpodoxime, proxetil, andenoxacin), caffeine, theophylline, and morphine. In another embodiment,the drug may be a biphosphonate or another drug used to treatosteoporosis. Non-limiting examples of a biphosphonate includealendronate, ibandronate, risedronate, zoledronate, pamidronate,neridronate, olpadronate, etidronate, clodronate, and tiludronate. Othersuitable drugs include estrogen, selective estrogen receptor modulators(SERMs), and parathyroid hormone (PTH) drugs. In yet another embodiment,the drug may be an antibacterial agent. Suitable antibiotics includeaminoglycosides (e.g., amikacin, gentamicin, kanamycin, neomycin,netilmicin, streptomycin, and tobramycin), carbecephems (e.g.,loracarbef) a carbapenem (e.g., certapenem, imipenem, and meropenem),cephalosporins (e.g., cefadroxil cefazolin, cephalexin, cefaclor,cefamandole, cephalexin, cefoxitin, cefprozil, cefuroxime, cefixime,cefdinir, cefditoren, cefoperazone, cefotaxime, cefpodoxime,ceftazidime, ceftibuten, ceftizoxime, and ceftriaxone), macrolides(e.g., azithromycin, clarithromycin, dirithromycin, erythromycin, andtroleandomycin), monobactam, penicillins (e.g., amoxicillin, ampicillin,carbenicillin, cloxacillin, dicloxacillin, nafcillin, oxacillin,penicillin G, penicillin V, piperacillin, and ticarcillin), polypeptides(e.g., bacitracin, colistin, and polymyxin B), quinolones (e.g.,ciprofloxacin, enoxacin, gatifloxacin, levofloxacin, lomefloxacin,moxifloxacin, norfloxacin, ofloxacin, and trovafloxacin), sulfonamides(e.g., mafenide, sulfacetamide, sulfamethizole, sulfasalazine,sulfisoxazole, and trimethoprim-sulfamethoxazole), and tetracyclines(e.g., demeclocycline, doxycycline, minocycline, and oxytetracycline).In an alternate embodiment, the drug may be an antiviral proteaseinhibitor (e.g., amprenavir, fosamprenavir, indinavir,lopinavir/ritonavir, ritonavir, saquinavir, and nelfinavir). In a stillanother embodiment, the drug may be a cardiovascular drug. Examples ofsuitable cardiovascular agents include cardiotonic agents (e.g.,digitalis (digoxin), ubidecarenone, and dopamine), vasodilating agents(e.g., nitroglycerin, captopril, dihydralazine, diltiazem, andisosorbide dinitrate), antihypertensive agents (e.g., alpha-methyldopa,chlortalidone, reserpine, syrosingopine, rescinnamine, prazosin,phentolamine, felodipine, propanolol, pindolol, labetalol, clonidine,captopril, enalapril, and lisonopril), beta blockers (e.g., levobunolol,pindolol, timolol maleate, bisoprolol, carvedilol, and butoxamine),alpha blockers (e.g., doxazosin, prazosin, phenoxybenzamine,phentolamine, tamsulosin, alfuzosin, and terazosin), calcium channelblockers (e.g., amlodipine, felodipine, nicardipine, nifedipine,nimodipine, nisoldipine, nitrendipine, lacidipine, lercanidipine,verapamil, gallopamil, and diltiazem), and anticlot agents (e.g.,dipyrimadole).

The bioactive can be in any form including in a solid, a gel, anemulsion, or any combination thereof. A solid, as used herein, caninclude a granule, a powder, or a crystal. In such cases, the bioactivecore may range in size from about 0.001 millimeters to 10 millimeters.In some embodiments, the bioactives are about 0.1 millimeters to 5millimeters. In a preferred embodiment, the bioactives are about 0.1millimeters to 3 millimeters.

(c). Composition

The composition comprising a layer formed over a core may be in avariety of configurations. The core may be in any shape including rods,spheroids, cylinders, and the like. Generally, the layer comprising thefirst polymer is formed over the core such as to completely surround thecore. In some embodiments, the core may be in direct contact with thelayer comprising the first polymer, and in other embodiments, one ormore additional layers are formed between the core and the layercomprising the first polymer. In alternate embodiments, one or moreadditional layers are formed over the layer comprising the firstpolymer.

In some embodiments, the composition comprises an additional layersubstantially that is hydrophobic. The hydrophobic layer may becomprised of a hydrophobic agent. Hydrophobic agents are generally thosewith a contact angle above 90°. In some embodiments, the hydrophobiclayer is comprised of a wax, a polymer, or a fatty acid, includingC₁₂-C₃₀ fatty acids, or a fatty acid ester, including monoglycerides,diglycerides, and triglycerides. In some embodiments, the hydrophobiclayer is chosen from canola oil, coconut oil, corn oil, cottonseed oil,lauric acid, linoleic acid, oleic acid, palm oil, palmitic acid, soyoil, soybean oil, stearic acid, stearin, sunflower seed oil, vegetableoil, or the hydrogenated forms of any of these, and combinationsthereof.

In some embodiments, the composition comprises an additional layer thatis substantially hydrophilic. The hydrophilic layer is comprised ofwater soluble molecules and dissolves in water. In preferredembodiments, the hydrophilic layer is chosen fromhydroxymethylcellulose, hydroxypropylcellulose, methylcellulose,ethylcellulose, carboxymethyl cellulose, and combinations thereof.

In one embodiment, the additional layer is a mixture of a non-reactivewax and a carbonate as described in section (VI).

The additional layer(s) can be provided in a variety of thicknessesaround the core or layer. The amount of material comprising theadditional layer may range from about 1% to about 75% of the totalweight of the composition (core and layer(s)). In other embodiments, theamount of material comprising the additional layer may range from about1% to about 50% of the total weight of the composition. In variousembodiments, the amount of material comprising the layer is about 1% toabout 10%, about 5% to about 15%, about 10% to about 20%, about 15% toabout 25%, about 20% to about 30%, about 25% to about 35%, about 30% toabout 40%, about 35% to about 45%, or about 40% to about 50% of thetotal weight of the composition. In particular embodiments, theadditional layer is about 5%, about 10%, about 15%, or about 20% of thetotal weight of the composition.

A variety of commonly used excipients in pharmaceutical and nutritiveformulations may be utilized with any bioactives described above.Non-limiting examples of suitable excipients include an agent selectedfrom the group consisting of non-effervescent disintegrants, a coloringagent, a flavor-modifying agent, an oral dispersing agent, a stabilizer,a preservative, a diluent, a compaction agent, a lubricant, a filler, abinder, taste masking agents, an effervescent disintegration agent, andcombinations of any of these agents. In some embodiments, the additionallayer may further comprise a polymer having a repeat unit of Formula(I).

In one embodiment, the excipient may be a disintegrant or asuperdisintegrant. Suitable disintegrants include, without limit,starches (such as corn starch, potato starch, and the like),pregelatinized and modified starches thereof, micro-crystallinecellulose (including, but not limited to ethyl cellulose, methylcellulose or combinations thereof), alginates, sodium starch glycolate,and gums (such as agar, guar, locust bean, karaya, pectin, andtragacanth). Non-limiting examples of suitable superdisintegrantsinclude crospovidine, sodium carboxymethylcellulose, croscarmellosesodium, sodium starch glycolate, low substituted hydroxypropylcellulose, and sodium bicarbonate. In one preferred embodiment, thecomposition may comprise sodium carboxymethylcellulose as asuperdisintegrant.

(d). Properties

The compositions comprising the layer comprising a first polymer mayhave improved physical properties including pH switch properties,improved release profiles for the bioactive, and improved mechanicalproperties.

The layer comprising the first polymer may have a pH switch effect wherethe compositions are stable in an aqueous solution under approximatelyneutral pH, but hydrolyze at a lower pH. For example, the layercomprising the first polymer is stable at a pH of about 6.0, about 6.5,about 7.0, and about 7.5. The compositions comprising the first polymerhydrolyze in an aqueous solution having a pH of less than about pH 5.0.

Hydrolysis of the composition results in release of the bioactive fromthe composition comprising the first layer. Accordingly, thecompositions may be used to achieve a particular release profile for thebioactive agent.

At an approximately neutral pH, the compositions may be characterized byminimal release of the bioactive. In one embodiment, a minimal releaseprofile may show a release profile substantially similar to the pH 6.5release profiles shown in FIG. 1, 2, 3, 4, 6, 8, or 9. In anotherembodiment, at an approximately neutral pH, release is characterized byless than 20% of the total bioactive being released from thecomposition. In still other embodiments, a minimum release ischaracterized by less than 19%, less than 18%, less than 17%, less than16%, less than 15%, less than 14%, less than 13%, less than 12%, lessthan 11%, less than 10%, less than 9%, less than 8%, less than 7%, lessthan 6%, less than 5%, less than 4%, less than 3%, less than 2%, or lessthan 1% of the total bioactive in the composition being released.

At a pH of less than 5.0, the compositions may have a release profilefor the bioactive which is substantially constant, first-order,sigmoidal, or delayed. Generally, the release rate at a pH of less than5.0 is higher than the release rate at approximately neutral conditions.In some embodiments, the compositions have a release profile that issubstantially similar to the release profiles at pH 2.5 release profilesshown in FIG. 1, 2, 3, 6, 8, or 9. In one preferred embodiment, releaseat a pH of less than 5.0 is substantially constant. A substantiallyconstant release refers to release of a bioactive that is constant overa period of time, for example, varying by less than 1%, less than 0.5%,or 0.25% in different embodiments. The compositions may show a constantrelease rate at a pH below about 5.0 for a period of 1 to 24 hours. Insome embodiments, the release rate is constant over a period of about 1hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours,about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours,about 20 hours, about 21 hours, about 22 hours, about 23 hours, or about24 hours. Depending on the time period and pH, the release of thebioactive may range from less than 1% per hour to more than 30% perhour. The release profile is tunable based on the amount of the firstpolymer in the layer. Higher percentages of the first polymer in thelayer correspond to a higher percentage of bioactive released per hour,while lower amounts of the first polymer correspond to a lowerpercentage release per hour.

In still another embodiment, the release profile may show an initialhigh rate of release at a pH of less than 5.0. In such embodiments, therelease rates at a pH of 5.0 or lower may be greater over the first 1 to5 hours at a pH of 5.0 or lower. In some embodiments, this initialperiod of rapid release of bioactive is followed by a period of constantrelease.

The compositions of the invention have improved durability, plasticity,and mechanical properties. Such properties are advantageous forcompositions that may be subject to mastication (i.e. in the context ofproviding the composition to an animal) or in the context of mechanicalstresses of industrial processing such as mixing and conveyingequipment. Resiliency of the compositions against mechanical force canbe measured by the impact test described in Example 8. In someembodiments, the compositions of the invention release less than 10% ofthe total bioactive when subjected to 25 impacts. In other embodiments,the compositions of the invention release less than 9%, or less than 8%or less than 7%, or less than 6% or less than 5%, or less than 4%, orless than 3%, or less than 2% or less than 1% of the bioactive whensubjected to 25 impacts.

II. Matrix Composition

The disclosure also provides an agglomerated composition comprising aplurality of bioactive agents embedded in a matrix. The matrix comprisesa first polymer comprising a repeat unit of Formula (I).

(a). Agglomerated Composition

The agglomerated composition comprises a plurality of bioactive agentsembedded in a matrix. The matrix comprises a first polymer comprising arepeat unit of Formula (I). The first polymer is described in section(I)(a). Suitable bioactive agents for use in the matrix are described insection (I)(b)(i).

The agglomerated composition comprises a plurality of bioactive agentsembedded in a matrix. The agglomerated composition formed by the matrixand bioactive agents can be in any shape including rods, spheroids,cylinders, and the like. Additionally, the agglomerated composition canbe shaped for a particular need. For, example, the agglomeratedcomposition can be shaped to cap open ends of a cylinder.

The bioactive can be present in the agglomerated composition in a weightof about 20% to about 90% of the total composition. In some embodimentsthe bioactive is about 10%, about 15%, about 20%, about 25%, about 30%,about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about65%, about 70%, about 80%, about 90%, or about 99% by weight of thetotal composition. In a preferred embodiment, the bioactive is presentin an amount of about 80% to about 90%, or 85% to about 95%, or about95% to about 99% by weight of the total composition.

The bioactive agents may be embedded in the matrix in a variety of waysdepending on the shape and intended use of the agglomerated composition.In some embodiments, the bioactive agents are homogeneously dispersed inthe matrix composition, meaning that the bioactive is provided inapproximately the same concentration throughout the matrix. In otherembodiments, the bioactive agents may be more or less concentrated incertain parts of the matrix. When one or more bioactive agents are inthe matrix, they may either be dispersed approximately homogeneously, orordered within the matrix. For example, in embodiments where more thanone bioactive is present, the bioactives may be laterally separated inthe composition. In other embodiments, the bioactives may be more highlyconcentrated in the inner portion of the matrix than at the outersurface of the matrix.

The agglomerated composition may comprise at least one additional agentin the matrix. The additional agent may be chosen from polymers,including crystalline and semi-crystalline polymers. Examples ofsuitable polymers, without limitation, are polymers of acrylates,aminoacrylates, alkylene succinates, alkylene oxalates, amides, aminoacids, anhydrides, arylates, carbonates, cellulose (including, but notlimited to ethyl cellulose, methyl cellulose or combinations thereof),caprolactone, cyanoacrylates, dihydropyrans, dioxanes, dioxanones, etherether ketones, ethylene glycol, fumarates, hydroxyalkanoates,hydroxyl-esters, imides, ketals, lactides, methacrylates, methylolefins, orthoesters, phosphazines, styrenes, terephthalates,trimethylene carbonate, urathanes, vinyl acetates, vinyl ketones, vinylhalides, derivatives, isomers, and mixtures thereof. In someembodiments, the additional agent may be chosen from polyacrylamide,polystyrene, polyvinylpyrrolidone, polyvinylacetate. The additionalagent may also be a wax, including natural and synthetic waxes, fattyacids, including C₁₂-C₃₀ fatty acids, and fatty acid esters includingmonoglycerides, diglycerides, and triglycerides and hydrogenated fattyacid esters, non-limiting examples include canola oil, coconut oil, cornoil, cottonseed oil, lauric acid, linoleic acid, oleic acid, palm oil,palmitic acid, soy oil, soybean oil, stearic acid, stearin, sunflowerseed oil, vegetable oil, and combinations thereof. The oils may behydrogenated, non-hydrogenated or partially hydrogenated. The additionalagent may also be a flow agent such as a carbonate, talc, magnesiumstearate and the like. Carbonates may be selected from copper carbonate,zinc carbonate, calcium carbonate, magnesium carbonate, potassiumcarbonate, sodium carbonate, and combinations thereof. The additionalagent may also be a bicarbonate, including potassium bicarbonate oranother alkali metal bicarbonate. In a preferred embodiment, theadditional agent is a cellulose polymer selected fromhydroxymethylcellulose, hydroxyproplycellulose, methylcellulose,carboxymethyl cellulose and ethylcellulose. The additional agent may bea salt of an above listed compound including alkali metal salts such ascalcium, magnesium, potassium, sodium, lithium and the like.

In one embodiment, the additional agent is a pH-sensitive polymer andmay be chosen from natural and modified polymers (e.g. chitosan)including blends with monomers. The additional agents may be amino typepolymers. Amino type polymers include, but are not limited to, pyridine,pyridine derivatives, amino acrylate type monomers, such as dialkylaminoethyl acrylate, styrene, styrene derivatives (such aspoly-2-vinylpyridine-co-styrene), acrylonitrile, acrylate type monomersof acrylic acid, vinyl esters, vinyl acetate, and vinyl substitutedheterocyclic rings that contain nitrogen fusions (such as vinylcarbazole, vinyl quinolone and N-vinylpyrrole). In one preferredembodiment, the additional agent is poly-2-vinylpyridine-co-styrene.

In one alternative embodiment, the agglomerated composition is free fromethylcellulose.

In some embodiments, the first polymer is about 5% to about 50% byweight of the matrix and the additional agent comprises from about 50%to about 95% by weight of the matrix. In various embodiments, theadditional agent(s) comprise about 50%, about 60%, about 70%, about 80%,or about 90% of the matrix. In various embodiments, where two or moreadditional agents are present with the first polymer in the matrix, theadditional agents can be present in any ratio without limitation.

(b). Optional Layers

In some embodiments, the matrix composition may be coated by at leastone layer. The layer may be as described in section (I), orsubstantially hydrophilic or substantially hydrophobic. As will beunderstood by the skilled artisan, different layers can be combined andlayered on the agglomerated composition.

In some embodiments, the layer is substantially hydrophobic. Thehydrophobic layer may be comprised of a hydrophobic agent. Hydrophobicagents are generally those with a contact angle above 90°. In someembodiments, the hydrophobic layer is comprised of a wax, a polymer, afatty acid including C₁₂-C₃₀ fatty acids, or fatty acid esters,including monoglycerides, diglycerides, and triglycerides. Non-limitingexamples include canola oil, coconut oil, corn oil, cottonseed oil,lauric acid, linoleic acid, oleic acid, palm oil, palmitic acid, soyoil, stearic acid, stearin, sunflower seed oil, vegetable oil, andcombinations thereof. The oils may be hydrogenated, non-hydrogenated, orpartially hydrogenated.

In various embodiments, the layer is substantially hydrophilic. Ahydrophilic layer, in contrast to a hydrophobic layer, compriseshydrophilic components. In preferred embodiments, the hydrophilic layeris chosen from hydroxymethylcellulose, hydroxyproplycellulose,methylcellulose, ethylcellulose, carboxymethyl cellulose, andcombinations thereof.

A variety of commonly used excipients in pharmaceutical and nutritiveformulations may be utilized with any such agents described above.Non-limiting examples of suitable excipients include an agent selectedfrom the group consisting of non-effervescent disintegrants, a coloringagent, a flavor-modifying agent, an oral dispersing agent, a stabilizer,a preservative, a diluent, a compaction agent, a lubricant, a filler, abinder, taste masking agents, an effervescent disintegration agent, andcombinations of any of these agents.

The matrix comprising the first polymer may also have a pH switch effectwhere the compositions are stable in an aqueous solution underapproximately neutral pH, but hydrolyze at a lower pH. For example, thematrix comprising the first polymer is stable at a pH level of about6.0, about 6.5, about 7.0, and about 7.5, but the matrix comprising thefirst polymer hydrolyzes in an aqueous solution having a pH of less thanabout pH 5.0.

Hydrolysis of the composition results in release of the bioactive fromthe composition comprising the first layer. Accordingly, thecompositions may be used to achieve a particular release profile for thebioactive agent.

At an approximately neutral pH, the compositions may be characterized byminimal release of the bioactive. In one embodiment, a minimal releasemay show a release profile substantially similar to the pH 6.5 releaseprofiles shown in FIG. 1, 2, 3, 4, 5, 6, 8, or 9. In another embodiment,at an approximately neutral pH, release is characterized by less than20% of the total bioactive being released from the composition. In stillother embodiments, a minimum release is characterized by less than 19%,less than 18%, less than 17%, less than 16%, less than 15%, less than14%, less than 13%, less than 12%, less than 11%, less than 10%, lessthan 9%, less than 8%, less than 7%, less than 6%, less than 5%, lessthan 4%, less than 3%, less than 2%, or less than 1% of the totalbioactive in the composition.

At a pH of less than 5.0, the compositions may have a release profilewhich is substantially constant, first-order, sigmoidal, or delayed.Generally, the release rate at a pH of less than 5.0 is higher than therelease rate at approximately neutral conditions. In some embodiments,the compositions have a release profile that is substantially similar tothe release profiles at pH 2.5 release profiles shown in FIG. 1, 2, 3,5, 6, 8, or 9. In one preferred embodiment, release at a pH of less than5.0 is substantially constant. A substantially constant release refersto release of a bioactive that is constant over a period of time. Thecompositions may show a constant release rate at a pH below 5.0 for aperiod of 1 to 24 hours. In some embodiments, the release rate isconstant over a period of about 1 hour, about 2 hours, about 3 hours,about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours,about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours,about 22 hours, about 23 hours, or about 24 hours. Depending on the timeperiod and pH, the release of the bioactive may range from less than 1%per hour to more than 30% per hour. In one embodiment, the compositionhas a constant release rate of about 10% of the bioactive per hour at apH of 2.5.

In still another embodiment, the release profile may show an initialhigh rate of release at a pH of less than 5.0. In such embodiments, therelease rates at a pH of 5.0 or lower may be greater over the first 1 to5 hours at a pH of 5.0 or lower. In some embodiments, this initialperiod of rapid release of bioactive is followed by a period of constantrelease.

The compositions of the invention have improved durability, plasticity,and mechanical properties. Such properties are advantageous forcompositions that may be subject to mastication (i.e. in the context ofproviding the composition to an animal) or in the context of mechanicalstresses of industrial processing such as mixing and conveyingequipment. Resiliency of the compositions against mechanical force canbe measured by the impact test described in Example 8. In someembodiments, the compositions of the invention release less than 10% ofthe total bioactive when subjected to 25 weight impacts. In otherembodiments, the compositions of the invention release less than 9%, orless than 8% or less than 7%, or less than 6% or less than 5%, or lessthan 4%, or less than 3%, or less than 2% or less than 1% of thebioactive when subjected to 25 weight impacts.

III. Food Composition

A further aspect of the disclosure provides a food compositioncomprising (i) a nutritive source and (ii) a composition comprising atleast one bioactive agent and a polymer having a repeat unity of Formula(I) as detailed above in sections (I) and (II). The nutritive source maybe a carbohydrate source, a protein source, a fat source, orcombinations thereof. In some aspects, the nutritive source is providedby the layer or matrix composition. The food composition may beformulated as a liquid, dry pellet, powder, or emulsion.

A variety of carbohydrate sources may be included as the nutritivesource in the food composition. The carbohydrate source may be of plant,microbial, or animal origin. Examples of suitable plant sources ofcarbohydrates include, without limit, grains such as wheat, oats, rice,rye, and so forth; legumes such as soy, peas, beans, and the like; corn;grasses; potatoes; vegetable plants; and plant fruits. The carbohydratemay be a monosaccharide such as pentose, glucose, galactose, and soforth; a disaccharide such as sucrose, lactose, maltose, and the like;an oligosaccharide such as a fructo-oligosaccaride,galactose-oligosaccaride, mannan-oligosaccharide, etc.; or apolysaccharide such as starch, glycogen, cellulose, arabinoxylan,pectin, gum, chitins, and so forth.

Numerous protein sources may be included in the food composition. Theprotein source may be derived from a plant. Non-limiting examples ofsuitable plants that provide a good source of protein include amaranth,arrowroot, barley, buckwheat, canola, cassava, channa (garbanzo),legumes, lentils, lupin, maize, millet, oat, pea, potato, rice, rye,sorghum, soybean, sunflower, tapioca, triticale, wheat, seagrasses, andalgae. Alternatively, the protein source maybe derived from an animal.For example, the animal protein source may be derived from a dairyproduct, bird eggs, or from the muscles, organs, connective tissues, orskeletons of land-based or aquatic animals.

A variety of fat sources are suitable for use as the nutritive source inthe food composition. The fat source may be of plant, animal, ormicrobial origin. Non-limiting examples of plant derived fats includevegetable oils (e.g., canola oil, corn oil, cottonseed oil, palm oil,peanut oil, safflower oil, soybean oil, and sunflower oil) and oilseeds(e.g., canola seeds, cottonseeds, flax seeds, linseeds, Niger seeds,sesame seeds, soy beans, and sunflower seeds), distillers grains, oralgae. Animal derived fats include, without limit, fish oils (e.g.,menhaden oil, anchovy oil, albacore tuna oil, cod liver oil, herringoil, lake trout oil, mackerel oil, salmon oil, and sardine oil), highfat fish meal (e.g., menhaden meal, anchovy meal, herring meal, pollackmeal, salmon meal, tuna meal, and whitefish meal), and animal fats(e.g., poultry fat, beef tallow, butter, pork lard, and whale blubber).

The amount of nutritive agent present in the food composition can andwill vary depending upon the ingredients present in the food compositionand its intended use. In general, the amount of nutritive source presentin the food composition may range from about 1% to about 99% by weightof the food composition. In various embodiments, the amount of nutritivesource present in the food composition may range from about 1% to about3%, from about 3% to about 10%, from about 10% to about 30%, or fromabout 30% to about 99% by weight of the food composition. Similarly, theamount of the composition detailed in sections (I) or (II) present inthe food composition can and will vary. In certain embodiments, theamount of a composition comprising at least one bioactive agent and apolymer having a repeat unity of Formula (I) present in the foodcomposition may range from about 1% to about 3%, from about 3% to about10%, from about 10% to about 30%, or from about 30% to about 99% byweight of the food composition.

In some aspects, a nutritive is provided by the hydrolysis product ofthe first polymer comprising Formula (I). In some embodiments thepolymer is not available as a nutritive agent until it is hydrolyzedfrom the first polymer. In one preferred embodiment, the nutritive agentis a methionine source, preferably 2-hydroxy-4-methylthiobutanoic acid

IV. Method for Providing a Bioactive Agent to a Subject

Still another aspect of the present disclosure encompasses a method fromproviding at least one bioactive agent to a subject. The methodcomprises administering to the subject a composition comprising thebioactive agent, wherein the composition comprising the bioactive agentis detailed above in sections (I)-(III).

The composition comprising the bioactive agent may be administered byvariety of routes such as, e.g., oral, transmucosal, topical, orparenteral. A preferred route of administration is oral. The compositionmay be administered to the subject as a particulate, as solid dosageform (e.g., tablet, caplet, capsule, etc.), as a liquid, or as a powderor granulate. The composition may be administered once a week, severaltimes a week, once a day, or two or more times a day.

The composition may be administered to a variety of subjects. Suitablesubjects include humans, food animals, companion animals, researchanimals, and zoo animals. Non-limiting examples of food animals includeruminants (e.g., beef cattle, dairy cows, sheep, goats, and bison) andmonogastrics (e.g., pigs and avian such as chickens, ducks, emu, gamehens, geese, guinea fowl/hens, quail, ostriches, and turkeys).Additional monogastric species include aquatic species (e.g., fish andcrustaceans including, but not limited to, salmon, shrimp, carp, tilapiaand shell fish). Suitable companion animals include, but are not limitedto, cats, dogs, horses, rabbits, rodents (e.g., mice, rats, hamsters,gerbils, and guinea pigs), hedgehogs, and ferrets. Examples of researchanimals include rodents, cats, dogs, rabbits, pigs, and non-humanprimates. Non-limiting examples of suitable zoo animals includenon-human primates, lions, tigers, bears, elephants, giraffes, and thelike. In a preferred embodiment the subject is a ruminant. Non-limitingexamples of ruminants include cattle, sheep, goats, bison, deer, moose,elk, reindeer, caribou, camels, giraffes, antelope, and llama.

The layer or matrix composition having a repeat unit comprising Formula(I) is stable in an aqueous solution under approximately neutral pH. Forexample, the composition is stable at a pH level of about 6.0, about6.5, about 7.0, and about 7.5. The composition comprising the bioactiveagent hydrolyzes in an aqueous solution having a pH of less than aboutpH 5.0. Hydrolysis of the layer or matrix composition releases thebioactive agent. Thus, at pH levels less than about 5.0, the compositionundergoes hydrolysis and releases the bioactive agent.

In embodiments in which the subject is a ruminant, therefore, thecomposition remains stable and is not degraded during the time in whichthe composition is in the rumen of the subject. Upon entry intoabomasum, in which the pH is low, the composition hydrolyzes andreleases the bioactive agent. Accordingly, the compositions may be usedfor rumen bypass as the bioactives are protected by the unhydrolyzedmatrix composition and are selectively released in the low pHenvironment of the abomasum.

V. Methods of Making Matrix and Layer Compositions

The processes used to form the layer and matrix compositions can andpreferably will vary. By way of non-limiting example, the desired amountof the first polymer, the bioactive, and any additional agents arecombined. In various aspects the agents may be combined in the presenceof water or an organic solvent, such as methanol or ethanol. The mixturemay be further processed before shaping into a suitable delivery form asdescribed in sections (I) and (II). In some embodiments, ingredients areextruded, granulated, blended, or processed through a hot melt processprior to shaping.

The matrix compositions may be shaped in any way including manually orby a press or die. The layers of the invention may be formed over a coreby methods generally known in the art, such as by dry powder layering,hand applying, by or by a fluid bed process, for example using a solventor a hot melt. Detailed information concerning materials, equipment andprocesses for preparing and applying an outer layer over in inner coremay be found in Pharmaceutical Dosage Forms: Tablets, eds. Lieberman etal. (New York: Marcel Dekker, Inc., 1989), and in Ansel et al.,Pharmaceutical Dosage Forms and Drug Delivery Systems, 6^(th) Ed.(Media, Pa.: Williams & Wilkins, 1995).

VI. Layer Compositions Comprising a Compound of Formula (V)

In still another aspect, the present disclosure provides a layercomposition comprising the compound of Formula (V). The compositioncomprising the layer is formed over a core, the core comprising abioactive agent and the layer comprising non-reactive fatty acid esterand a carbonate. The core may be any core as described in section(I)(b). Suitable bioactive agents include those described in section(I)(b)(i).

The layer comprises a polymer having a repeat unit of Formula (V):

-   -   wherein,        -   R² is CH₃;        -   R³ is chosen from hydrogen, hydrocarbyl, and substituted            hydrocarbyl;        -   n is zero; and        -   m is an integer >1.

R³ can be chosen from hydrogen, hydrocarbyl and substituted hydrocarbyl.In one embodiment, R³ is an alkyl having 1 to 6 hydrocarbons. In apreferred embodiment, R³ is hydrogen.

The molecular weight can and will vary in different embodiments. Themolecular weight can range between 1,000 Da and about 200,000 Da. Invarious embodiments, the molecular weight of the polymer is about 2,000,10,000, 20,000 Da, 30,000 Da, 40,000 Da, 50,000 Da, 60,000 Da, 70,000Da, 80,000 Da, 90,000 KDa, 100,000 Da, or a number between any two ofthese values. The weight of a mixture of polymers may be characterizedby its mass-average molecular weight. In some aspects, the mass-averagemolecular weight of the polymers may be at least 500 KDa. In otheraspects, the mass average molecular weight ranges from about 1,000 Da toabout 100,000 Da.

In some aspects of the invention, Formula (V) may have chiral centers.In particular, the carbon alpha to the carbonyl unit in the compound ofFormula (I), (II), or (Ill) may be chiral and may have an R or an Sconfiguration. In some embodiments, the configuration at this positionmay be R. In other embodiments, the configuration at this position maybe S. In various aspects, the repeat units may be all R, all S, orcomprise a combination of R and S repeat units, for example, theconfiguration of the repeat units may alternate in block or randomly.

The layer may further comprise another polymer. Suitable polymers mayinclude crystalline and semi-crystalline polymers. Examples of suitablepolymers, without limitation, are polymers of acrylates, aminoacrylates,alkylene succinates, alkylene oxalates, amides, amino acids, anhydrides,arylates, carbonates, cellulose (including, but not limited to,hydroxymethylcellulose, hydroxyproplycellulose, methylcellulose,carboxymethyl cellulose and ethylcellulose), caprolactone,cyanoacrylates, dihydropyrans, dioxanes, dioxanones, ether etherketones, ethylene glycol, fumarates, hydroxyalkanoates, hydroxyl-esters,imides, ketals, lactides, methacrylates, methyl olefins, orthoesters,phosphazines, styrenes, terephthalates, trimethylene carbonate,urathanes, vinyl acetates, vinyl ketones, vinyl halides, derivatives,isomers, and mixtures thereof.

In one preferred embodiment, the additional agent is the polymercomprising the repeat unit of Formula (I) as described in section(I)(a). In a particularly preferred embodiment, the polymer is thecompound of Formula (III).

The layer comprising the polymer having the repeat unit of Formula (V)is stable in an aqueous solution under approximately neutral pH. Forexample, the layer is stable at a pH level of about 6.0, about 6.5,about 7.0, and about 7.5. The layer hydrolyzes in an aqueous solutionhaving a pH of less than about pH 5.0. Hydrolysis of the layer releasesthe bioactive agent. Thus, at pH levels from about pH 1.0 to about pH4.5, the layer undergoes hydrolysis and releases the bioactive agent.

In embodiments in which the subject is a ruminant, therefore, the layerremains stable and is not degraded during the time in which thecomposition is in the rumen of the subject. Upon entry into abomasum, inwhich the pH is low, the layer hydrolyzes and releases the bioactiveagent. In a preferred embodiment, the bioactive agent is2-hydroxy-4-methylthiobutanoic acid (HMTBa).

VII. Agglomerated Compositions Comprising a Compound of Formula (V)

In another aspect, the present disclosure provides an agglomeratedcomposition comprising a plurality of bioactive agents embedded in amatrix. The matrix comprises the compound of Formula (V) with thebioactive agents. Suitable bioactive agents for use in the matrix aredescribed in section (I)(a)(i). The composition comprising Formula (V)is described in section (VI).

The agglomerated composition comprises a plurality of bioactive agentsembedded in a matrix. The agglomerated composition formed by the matrixand bioactive agents can be in any shape including rods, spheroids,cylinders, and the like. Additionally, the agglomerated composition canbe shaped for a particular need. For, example, the agglomeratedcomposition can be shaped to cap open ends of a cylinder.

The bioactive can be present in the agglomerated composition in a weightof about 20% to 80% of the total composition. In some embodiments thebioactive is about 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, or 80% of the total composition. In a preferredembodiment, the bioactive is present in an amount of about 50 to about66% of the total agglomerated composition.

The agglomerated composition may further comprise another polymer.Suitable polymers may include crystalline and semi-crystalline polymers.Examples of suitable polymers, without limitation, are polymers ofacrylates, aminoacrylates, alkylene succinates, alkylene oxalates,amides, amino acids, anhydrides, arylates, carbonates, cellulose(including, but not limited to, hydroxymethylcellulose,hydroxyproplycellulose, methylcellulose, carboxymethyl cellulose andethylcellulose), caprolactone, cyanoacrylates, dihydropyrans, dioxanes,dioxanones, ether ether ketones, ethylene glycol, fumarates,hydroxyalkanoates, hydroxyl-esters, imides, ketals, lactides,methacrylates, methyl olefins, orthoesters, phosphazines, styrenes,terephthalates, trimethylene carbonate, urathanes, vinyl acetates, vinylketones, vinyl halides, derivatives, isomers, and mixtures thereof.

In one preferred embodiment, the polymer is the compound of comprisingthe repeat unit of Formula (I) as described in section (I)(a). In aparticularly preferred embodiment, the polymer is comprises the repeatunit of Formula (III).

The matrix is stable in an aqueous solution under approximately neutralpH. For example, the matrix is stable at a pH level of about 6.0, about6.5, about 7.0, and about 7.5. The matrix hydrolyzes in an aqueoussolution having a pH of less than about pH 5.0. Hydrolysis of the matrixreleases the bioactive agent.

In embodiments in which the subject is a ruminant, therefore, theagglomerated composition remains stable and is not degraded during thetime in which the composition is in the rumen of the subject. Upon entryinto abomasum, in which the pH is low, the matrix hydrolyzes andreleases the bioactive agent. In a preferred embodiment, the bioactiveagent is 2-hydroxy-4-methylthiobutanoic acid (HMTBa).

VIII. Layer Compositions Comprising a Non-Reactive Wax and a Carbonate

In another aspect, the invention provides a composition comprising alayer formed over a core, the core comprising a bioactive agent and thelayer comprising non-reactive fatty acid ester and a carbonate. The coremay be any core as described in section (I)(b). Suitable bioactiveagents include those described in section (I)(b)(i).

The layer composition may be a mixture of a non-reactive wax and acarbonate. A non-reactive wax is a wax which does not interactappreciably with a carbonate and does not form carboxylate or fatty acidsalts. In some embodiments, the non-reactive fat does not have a freecarboxylic acid group. The non-reactive wax can be chosen fatty acidesters including fatty acid glycerol esters including monoglycerides,diglycerides, and triglycerides. In one preferred embodiment, thenon-reactive wax is stearin. In another embodiment, the wax ishydrogenated soy or vegetable oil or a paraffin.

Carbonates may be selected from copper carbonate, zinc carbonate,calcium carbonate, magnesium carbonate, potassium carbonate, sodiumcarbonate, and combinations thereof. The amount of carbonate in thelayer can and will vary. The amount of carbonate may range from about 1%to about 60%, or more preferably from about 15% to about 50% of thetotal weight of the layer. In another embodiment, the non-reactive waxis stearin and the carbonate is zinc carbonate.

Without being bound to any theory, it is thought that the non-reactivewax preserves the solubility of the carbonate so the carbonate candissolve out of the wax matrix in some embodiments and form pores in thestructure. The presence of a non-reactive wax also preserves thecarbonate so that it may react with an acid external to the layer toproduce CO₂, which promotes further fracturing of the layer. The resultis a porous composition. In some embodiments, the carbonate is presentin the wax in a weight to weight ratio of about 20%, 30%, 40%, 50%, or60% or higher. In some preferred embodiments, the carbonate comprisesfrom about 20% to about 50% of the total weight of the layer.

The layer may additionally comprise a bicarbonate. Suitable bicarbonatesinclude alkali metal carbonates including sodium bicarbonate, potassiumcarbonate, calcium carbonate, magnesium carbonate, lithium carbonate andthe like. When bicarbonate is present, it may be present in a ratio ofabout 1% to about 10% of the layer. In some preferred embodiments,potassium bicarbonate is about 2% of the total weight of the layer.

The layer may additional comprise a disintegrant or a superdisintegrant. Suitable disintegrants include, without limit, starches(such as corn starch, potato starch, and the like), pregelatinized andmodified starches thereof, micro-crystalline cellulose, alginates,sodium starch glycolate, and gums (such as agar, guar, locust bean,karaya, pectin, and tragacanth). Non-limiting examples of suitablesuperdisintegrants include crospovidine, sodium carboxymethylcellulose,croscarmellose sodium, sodium starch glycolate, low substitutedhydroxypropyl cellulose, and sodium bicarbonate. In one preferredembodiment, the composition may comprise sodium carboxymethylcelluloseas a superdisintegrant. The disintegrant, when present, may be providedin a range of about 2% to about 20% of the total weight of the layer.

In some embodiments, the composition further comprises a reactive wax ora mixture of non-reactive and reactive waxes such as vegetable oil,cottonseed oil, or canola oil.

The layer comprising the non-reactive wax and carbonate is stable in anaqueous solution under approximately neutral pH. For example, the layeris stable at a pH level of about 6.0, about 6.5, about 7.0, and about7.5. The layer hydrolyzes in an aqueous solution having a pH of lessthan about pH 5.0. Hydrolysis of the layer facilitates release of thebioactive agent.

In embodiments in which the subject is a ruminant, therefore, the layerremains stable and is not degraded during the time in which thecomposition is in the rumen of the subject. Upon entry into abomasum, inwhich the pH is low, the layer hydrolyzes and releases the bioactiveagent.

In addition to a layer composition, the carbonate and wax may be formedinto an agglomerated composition as described in section (II). Thecarbonate and wax described herein may comprise the matrix to which aplurality of bioactives are embedded.

Definitions

When introducing elements of the embodiments described herein, thearticles “a”, “an”, “the” and “said” are intended to mean that there areone or more of the elements. The terms “comprising”, “including” and“having” are intended to be inclusive and mean that there may beadditional elements other than the listed elements.

The compounds described herein have asymmetric centers. Compounds of thepresent invention containing an asymmetrically substituted atom may beisolated in optically active or racemic form. All chiral,diastereomeric, racemic forms and all geometric isomeric forms of astructure are intended, unless the specific stereochemistry or isomericform is specifically indicated.

The term “acyl,” as used herein alone or as part of another group,denotes the moiety formed by removal of the hydroxyl group from thegroup COOH of an organic carboxylic acid, e.g., RC(O)—, wherein R is R¹,R¹O—, R¹R²N—, or R¹S—, R¹ is hydrocarbyl, heterosubstituted hydrocarbyl,or heterocyclo, and R² is hydrogen, hydrocarbyl, or substitutedhydrocarbyl.

The term “acyloxy,” as used herein alone or as part of another group,denotes an acyl group as described above bonded through an oxygenlinkage (O), e.g., RC(O)O— wherein R is as defined in connection withthe term “acyl.”

The term “allyl,” as used herein not only refers to compound containingthe simple allyl group (CH₂═CH—CH₂—), but also to compounds that containsubstituted allyl groups or allyl groups forming part of a ring system.

The term “alkyl” as used herein describes groups which are preferablylower alkyl containing from one to eight carbon atoms in the principalchain and up to 20 carbon atoms. They may be straight or branched chainor cyclic and include methyl, ethyl, propyl, isopropyl, butyl, hexyl andthe like.

The term “alkenyl” as used herein describes groups which are preferablylower alkenyl containing from two to eight carbon atoms in the principalchain and up to 20 carbon atoms. They may be straight or branched chainor cyclic and include ethenyl, propenyl, isopropenyl, butenyl,isobutenyl, hexenyl, and the like.

The term “alkoxide” or “alkoxy” as used herein is the conjugate base ofan alcohol. The alcohol may be straight chain, branched, cyclic, andincludes aryloxy compounds.

The term “alkynyl” as used herein describes groups which are preferablylower alkynyl containing from two to eight carbon atoms in the principalchain and up to 20 carbon atoms. They may be straight or branched chainand include ethynyl, propynyl, butynyl, isobutynyl, hexynyl, and thelike.

The term “aromatic” as used herein alone or as part of another groupdenotes optionally substituted homo- or heterocyclic conjugated planarring or ring system comprising delocalized electrons. These aromaticgroups are preferably monocyclic (e.g., furan or benzene), bicyclic, ortricyclic groups containing from 5 to 14 atoms in the ring portion. Theterm “aromatic” encompasses “aryl” groups defined below.

The terms “aryl” or “Ar” as used herein alone or as part of anothergroup denote optionally substituted homocyclic aromatic groups,preferably monocyclic or bicyclic groups containing from 6 to 10 carbonsin the ring portion, such as phenyl, biphenyl, naphthyl, substitutedphenyl, substituted biphenyl, or substituted naphthyl.

The term “crystalline polymer” as used herein refers to a polymer havingthe characteristic or regular three-dimensional packing.

The term “enrichment” means an amount above the statistical distributionif all chiral centers had an equal probability of being alpha or beta.

The terms “carbocyclo” or “carbocyclic” as used herein alone or as partof another group denote optionally substituted, aromatic ornon-aromatic, homocyclic ring or ring system in which all of the atomsin the ring are carbon, with preferably 5 or 6 carbon atoms in eachring. Exemplary substituents include one or more of the followinggroups: hydrocarbyl, substituted hydrocarbyl, alkyl, alkoxy, acyl,acyloxy, alkenyl, alkenoxy, aryl, aryloxy, amino, amido, acetal,carbamyl, carbocyclo, cyano, ester, ether, halogen, heterocyclo,hydroxyl, keto, ketal, phospho, nitro, and thio.

The terms “epoxy” or “epoxide” as used herein means a cyclic ether. Thering structure generally comprises from 2 to 5 carbon atoms in the ring.

The terms “halogen” or “halo” as used herein alone or as part of anothergroup refer to chlorine, bromine, fluorine, and iodine.

The term “heteroatom” refers to atoms other than carbon and hydrogen.

The term “heteroaromatic” as used herein alone or as part of anothergroup denotes optionally substituted aromatic groups having at least oneheteroatom in at least one ring, and preferably 5 or 6 atoms in eachring. The heteroaromatic group preferably has 1 or 2 oxygen atoms and/or1 to 4 nitrogen atoms in the ring, and is bonded to the remainder of themolecule through a carbon. Exemplary groups include furyl, benzofuryl,oxazolyl, isoxazolyl, oxadiazolyl, benzoxazolyl, benzoxadiazolyl,pyrrolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, pyridyl,pyrimidyl, pyrazinyl, pyridazinyl, indolyl, isoindolyl, indolizinyl,benzimidazolyl, indazolyl, benzotriazolyl, tetrazolopyridazinyl,carbazolyl, purinyl, quinolinyl, isoquinolinyl, imidazopyridyl, and thelike. Exemplary substituents include one or more of the followinggroups: hydrocarbyl, substituted hydrocarbyl, alkyl, alkoxy, acyl,acyloxy, alkenyl, alkenoxy, aryl, aryloxy, amino, amido, acetal,carbamyl, carbocyclo, cyano, ester, ether, halogen, heterocyclo,hydroxyl, keto, ketal, phospho, nitro, and thio.

The terms “heterocyclo” or “heterocyclic” as used herein alone or aspart of another group denote optionally substituted, fully saturated orunsaturated, monocyclic or bicyclic, aromatic or non-aromatic groupshaving at least one heteroatom in at least one ring, and preferably 5 or6 atoms in each ring. The heterocyclo group preferably has 1 or 2 oxygenatoms and/or 1 to 4 nitrogen atoms in the ring, and is bonded to theremainder of the molecule through a carbon or heteroatom. Exemplaryheterocyclo groups include heteroaromatics as described above. Exemplarysubstituents include one or more of the following groups: hydrocarbyl,substituted hydrocarbyl, alkyl, alkoxy, acyl, acyloxy, alkenyl,alkenoxy, aryl, aryloxy, amino, amido, acetal, carbamyl, carbocyclo,cyano, ester, ether, halogen, heterocyclo, hydroxyl, keto, ketal,phospho, nitro, and thio.

The terms “hydrocarbon” and “hydrocarbyl” as used herein describeorganic compounds or radicals consisting exclusively of the elementscarbon and hydrogen. These moieties include alkyl, alkenyl, alkynyl, andaryl moieties. These moieties also include alkyl, alkenyl, alkynyl, andaryl moieties substituted with other aliphatic or cyclic hydrocarbongroups, such as alkaryl, alkenaryl and alkynaryl. Unless otherwiseindicated, these moieties preferably comprise 1 to 20 carbon atoms.

The term “polymer” as used herein, means a molecule composed ofrepeating units. Polymer may refer to a homopolymer, i.e., a moleculecomprising single repeat unit, or a copolymer, i.e., containing morethan one repeat unit. Copolymers may be random or block. Polymer is usedinterchangeably with oligomer.

The term “protecting group” as used herein denotes a group capable ofprotecting a particular moiety, wherein the protecting group may beremoved, subsequent to the reaction for which the protection isemployed, without disturbing the remainder of the molecule. A variety ofprotecting groups and the synthesis thereof may be found in “ProtectiveGroups in Organic Synthesis” by T. W. Greene and P. G. M. Wuts, JohnWiley & Sons, 1999.

The term “semi-crystalline polymer” as used herein refers to a polymerwith regions that are “crystalline” as describe above, and regions thatare amorphous, having no regular packing to the three-dimensionalstructure.

The “substituted hydrocarbyl” moieties described herein are hydrocarbylmoieties which are substituted with at least one atom other than carbon,including moieties in which a carbon chain atom is substituted with aheteroatom such as nitrogen, oxygen, silicon, phosphorous, boron, or ahalogen atom, and moieties in which the carbon chain comprisesadditional substituents. These substituents include alkyl, alkoxy, acyl,acyloxy, alkenyl, alkenoxy, aryl, aryloxy, amino, amido, acetal,carbamyl, carbocyclo, cyano, ester, ether, halogen, heterocyclo,hydroxyl, keto, ketal, phospho, nitro, and thio.

The term “wax” as used herein can identify an oil, fatty acid, or afatty acid ester without limitation. The term “wax” as used hereinrefers to both compositions that are solid at room temperature and thosethat are liquid at room temperature.

Having described the invention in detail, it will be apparent thatmodifications and variations are possible without departing from thescope of the invention defined in the appended claims.

EXAMPLES

The following examples are included to illustrate, but not to limit theclaimed compositions and processes for delivering bioactive agents.

Example 1: Preparation of Coated Particles and In Vitro Release

A source of methionine was coated to protect it from degradation bybacteria but allow full absorption in the abomasum. For this, particlesof the calcium salt HMTBa (MHA®; Novus International) were coated with afirst coat comprising the HMTBa oligomer and a second coat comprising ahydrophobic material.

The first coat was either applied manually using a blender (neatmaterial) or via a fluid bed coating process (i.e., Wurster coating).For the manual method, the HMTBa oligomer (O) was mixed with a polymer,such as ethyl cellulose (EC), and blended with the methionine source.For the Wurster method, the HMTBa oligomer was mixed with the polymer ordissolved in a polar organic solvent, and sprayed on the methioninesource. In either method, a flow agent, such as talc (T), calciumstearate (CaSt), or CaCO₃ can be added to reduce tackiness. Typically,the HMTBa oligomer had a low content of monomer (e.g., 4% monomer).Table 1 details the parameters of the first coat of each particleprototype.

TABLE 1 Composition of Prototype Coated Particles - First Coat* EthylCalcium Coat Prototype # Oligomer Cellulose Talc Stearate CaCO₃ Level 117% — 11% — — manual 2 30% 70% — — — 22% 3 30% 70% — — —  5% 4 30% 70% —— — 10% 5 12.3%   — — — 17.5% manual 6 12.3   — — 11% — manual 7 12.3  — — 11% — manual *components presented as % of total

The second coat was applied to the oligomer-coated particles via a hotmelt or a fluid bed coating process. The hydrophobic material of thesecond coat comprised stearic acid (SA) and hydrogenated soybean oil(e.g., Dritex S (DS)). In some cases, the second coat also contained theHMTBa oligomer, EC, and/or CaCO₃. Table 2 details the parameters of thesecond coat of each particle prototype.

TABLE 2 Composition of Prototype Coated Particles - Second Coat TotalHMTBa Pro- Coat Load totype Stearic Dritex Level (core & # Acid* S*Oligomer* EC* CaCO₃ (%) coat) 1 1 1 — — — 25 57% 2 4 4 1 1 — 20 54% 3 12 — — — 25 61% 4 1 2 — — — 25 59% 5 1 2 — — 10% of 25 50% coat 6 1 2 — —10% of 10 68% coat 7 1 2 — — 10% of 25 55% coat *components presented asa ratio

The in vitro release of HMTBa was measured at different pH levels afterthe coated particles were incubated in pH 6.5 buffer solution for 16hours (to mimic the typical ruminal transit time). For the releasestudies, the coated particles were added to pH 2.5 or pH 6.5 buffersolutions. The solutions were shaken at for 24 hours. Samples wereremoved at 0, 2, 4, 6, 8, and 24 hours and analyzed by HPLC.

Prototype 1.

MHA® particles were manually coated with a first coat comprising HMTBaoligomer (17% of total) and talc (11% of total). The oligomer-coatedparticles were fluid bed coated with a 1:1 mixture of stearic acid andhydrogenated soybean oil to a coat level of 25%. The final load of HMTBaand HMTBa oligomer was 57%. The differential release profile is shown inFIG. 1A. There was substantially more release at pH 2.5 than at pH 6.5.At 24 hours, about 75% of the total HMTBa was released at pH 2.5, butless than 20% of the HMTBa was released at pH 6.5.

Prototype 2.

MHA® particles were coated with a first coat comprising a thin film ofethyl cellulose and oligomer. The thin film was applied by fluid bedcoating; i.e., 30% oligomer (6.7% monomer) and 70% EC were dissolved in1:1 acetone:ethanol and sprayed onto the MHA® particles. The coatingstep comprised spraying 12.2% solids (i.e., O+EC) to a coat level of22%. For the second coat, a hot melt coating of stearic acid,hydrogenated soybean oil, HMTBa oligomer, and ethyl cellulose (4:4:1:1)was used to coat the oligomer-coated particles to a 20% wax coat level.The final load of HMTBa (core and coat) was 54%. The release profile ispresented in FIG. 1B; the particles displayed pH dependent release(i.e., release at pH 2.5, but not at pH 6.5). The amount released waslow because these particles had a high degree of protection at low pH.

Prototypes 3 and 4.

MHA® particles were coated with a first coat comprising a thin film ofoligomer and ethyl cellulose. The coating was applied by fluid bedcoating; i.e., 30% O and 70% EC were dissolved in 1:1 acetone:ethanoland the particles were coated to a level of 5% for prototype 3 or a coatlevel of 10% for prototype 4. Each population of oligomer-coatedparticles was then coated with a second coat comprising a 2:1 mixture ofhydrogenated soybean oil and stearic acid to a coat level of 25%. Thefinal load of HMTBa (core and coat) was 61% and 59% for prototypes 3 and4, respectively. As shown in FIG. 1C, prototype 3 had better release atpH 2.5 than prototype 4 (i.e., 85% vs. about 45%, respectively). Neitherprototype had significant release at pH 6.5.

Prototype 5.

Core MHA® particles were manually coated with a first coat comprisingoligomer (12.3% of total) and CaCO₃ (17.5% of total). For the secondcoat, the oligomer-coated particles were fluid bed coated with a 2:1mixture of hydrogenated soybean oil and stearic acid containing CaCO₃(10% of coat) to a coat level of 15%. The total load of HMTBa (core andcoat) was 50%. As shown in FIG. 1D, release was greater at pH 2.5 thanpH 6.5 (e.g., 85% vs. 15% at 24 hours, respectively). Additionally,there was a high rate of release at pH 2.5 during the first 6 hours,which then decreased to a lower rate.

Prototypes 6 and 7.

MHA® particles were manually coated with a first coat comprising HMTBaoligomer (12.3% of total) and 11% Ca stearate (11% of total). For thesecond coat, the oligomer-coated particles were fluid bed coated with a2:1 mixture of hydrogenated soybean oil and stearic acid containingCaCO₃ (10% of coating) to a level of 10% for prototype 6 or a coat levelof 25% for prototype 7. The total load of HMTBa (core and coat) for eachof these was 68% and 55%, respectively. Prototypes 6 and 7 had similarrelease profiles at pH 2.5 (and both had very limited release at pH 6.5)(see FIG. 1E).

Example 2: In Situ Degradability of Coated Particles

Rumen stability is a necessary requirement for products to providemethionine activity to the tissues for protein synthesis. Escape valuesof >90% are considered sufficient for a rumen protected methioninesource to provide substantial methionine activity when the methioninesource is protected by physical means.

The seven prototype coated MHA® particles prepared in Example 1 wereevaluated for their in situ degradability characteristics. Rumencannulated steers were used to evaluate the rate and extent of rumendegradation of the prototypes as well as a reference formulation (i.e.,methionine granules coated with an amino-type polymer).

Three rumen cannulated steers [BW=606±4 kg] were fed a common diet basedon chopped alfalfa hay and ground corn for ad libitum consumption withan additional allotment of wheat straw for the 7 days of the experiment.Steers were weighed on day 2 and 5 of the experiment and feed offeredand refused was recorded daily. Realized dry matter intake for theexperimental period was 9.53 kg or 1.57% of body weight. Eighttreatments (i.e., prototypes 1-7 and reference formulation control) wereincubated in triplicate in each of the 3 steers for 48, 24, 6, and 0 (15minutes in the rumen to estimate solubility) hours. In situ bags (poresize ˜50 μm; 5 cm×10 cm) were preweighed and 1 g of sample was added toeach bag and sealed with a zip-tie yielding approximately therecommended 10 mg ingredient/cm² of bag surface area. Bags weresuspended in a mesh laundry bag, inserted in reverse order, withdrawnsimultaneously, hand washed in cold water until the wash water wasclear, and dried at 55° C. Dried bags with treatment were weighed and %dry matter lost was calculated.

Data were analyzed using the mixed procedure of SAS wherein sources ofvariation associated with steer, time of incubation, treatment and theinteraction between treatment and time were included. Differencesconsidered significant were P<0.05.

Degradation profiles for the prototype protected MHA® particles andreference formulation are shown in FIG. 2A. All treatments testedhad >90% of dry matter remaining after 48 hours in the rumen. Theproducts differed in the degree to which they were protected, i.e., someof the prototypes had relatively constant rates of release (e.g.,prototype #6) and some of the prototypes had extremely low levels ofrelease within the rumen (e.g., prototypes #4 and #7). Typical retentiontime within the rumen is between 12 and 20 hours for the particle phaseof rumen digesta. FIG. 2B shows the percent of dry matter remaining forthe different prototypes and the reference formulation after incubationin the rumen for 24 h. Retention time within the rumen is determined bya number of factors including: specific gravity, particle size,susceptibility to degradation, and the intake of the cow. Results ofthis experiment are relevant to the susceptibility to degradation, andby this metric all of the prototypes are considered to be quiteresistant to rumen degradation. The order of resistance is presented inTable 3 (based on 24 hour data where 1 is most resistant).

TABLE 3 In Situ Resistance to Degradation. Sample 1^(st) coat 2^(nd)coat Rank Prototype 1 O/T - manual SA/DS - 25% 8 Prototype 2 O/EC - thinfilm 22% SA/DA/O/EC - 30% 6 Prototype 3 O/EC - thin film 5% SA/DS - 25%3 Prototype 4 O/EC - thin film 10% SA/DS - 25% 2 Prototype 5 O/CaCO₃-manual SA/DS/CaCO₃- 25% 5 Prototype 6 O/CaSt - manual SA/DS/CaCO₃ - 10%7 Prototype 7 O/CaSt - manual SA/DS/CaCO₃ - 25% 1 Reference Amino-typepolymer coating 4 Formulation

Example 3: Preparation of Agglomerated Composition

The following example was designed to determine whether agglomeratedmatrix compositions would provide pH dependent release. MHA® powder wasgranulated with ethyl cellulose and HMTBa oligomer at 30% oligomer using15% solids. The powder was coated to 23% to a total load of HMTBa of50%. The granulated mixture was fluid bed coated with a 1:1 mixture ofhydrogenated soybean oil and stearic acid to a coat level of 25%. Therelease of HMTBa was measured at pH 2.5 or pH 6.5 after 16 hours at pH6.5 essentially as detailed above in Example 1. As shown in FIG. 3, theagglomerated composition displayed release in pH 2.5 buffer.

Example 4: Coated Particles Comprising Metal Carbonate

To determine whether a hydrophobic coating comprising a metal carbonatewould provide pH dependent release, the following coated particles wereprepared. “Blender O/Zn wax” particles were prepared by blender coatingMHA® particles with HMTBa oligomer (i.e., 7.5% or 12.4% oligomer, with atotal HMTBa load of 60-70%) and then over-coating the particles with a1:1 mixture of stearic acid and hydrogenated soybean oil containing30-40% Zn or Ca carbonate and 2-10% croscarmellose to a coat level of15, 20, or 25%. “Blender O/Oligo wax” particles were prepared by blendercoating MHA® particles with HMTBa oligomer (i.e., 7.5% or 12.4%oligomer, with a total HMTBa load of 60-70%) and then over-coating themwith a 1:1 mixture of stearic acid and hydrogenated soybean oilcontaining 10-60% oligomer (and optionally, methyl cellulose orcroscarmellose) to a coat level of 15, 20, or 25%. “MHA®/Zn wax”particles were prepared by coating MHA® particles with 1:1 mixture ofstearic acid and hydrogenated soybean oil containing 30-40% Zn or Cacarbonate and 2-10% croscarmellose to a coat level of 15, 20, or 25%.

To measure in vitro release, samples were incubated at pH 6.5 from time0 to hour 16 (i.e., rumen phase), pH 2.5 from hour 16 to hour 18 (i.e.,abomasum phase), and pH 6.5 from hour 18 to hour 40 (i.e., intestinephase). Aliquots were removed from each sample at predetermined timesand analyzed by HPLC. The release of the amino acid from allpreparations increased dramatically when the pH was lowered (see FIG.4). Some preparations (e.g., Blender O/Zn wax and Blender O/Oligo wax)exhibited slow rates of release at pH 6.5.

Example 5: Coated Particles Comprising Wax Overcoat

MHA® particles were coated with oligomer (as detailed above in Examples1 and 3) and over-coated with either of two “wax” coatings. The twocoatings were a “Zn wax” coat or an “oligomer wax” coat, which aredetailed below in Tables 4 and 5, respectively. The coatings wereapplied by fluid bed coating to coat levels of 15-25%. The wax of the Znwax coating comprised stearin (i.e., an ester of glycerol and stearicacid; stearin may be derived from palm oil and other oils), ahydrogenated vegetable oil (e.g., soy, canola, cotton seed, corn, etc.),or combinations thereof. The wax of the Oligomer wax coated comprisedstearin, hydrogenated vegetable oil, stearic acid, or combinationsthereof.

TABLE 4 Zn wax formulations. Proto- type Hydrogenated Zn Bicar- #Stearin Veg Oil Carbonate Croscarmellose bonate 8 20 g 20 g 40 g 10 g 09 53 g 0 40 g  5 g 2 g 10 0 55 g 35 g 10 g 0 11 32 g 32 g 31 g  5 g 0

TABLE 5 Oligomer wax formulations. Hydrogenated Stearic Ethyl PrototypeStearin Veg Oil Acid Cellulose Oligomer 12 18 g 18 g 10 g 2 g 35 g 13 015 g 15 g 5 g 30 g

Example 6: Simulated In Situ Release from Coated Particles

A series of coated MHA® particles were prepared in which the coatingcomprised HMTBa oligomer, stearic acid, poly-2-vinylpyridine-co-styrene(PVPS; MW ˜130-220K), and, optionally, ethyl cellulose and the coatinglevel varies from 10-15%. Table 6 presents the various formulations.

TABLE 6 Coat Level and Composition of Coated Particles Formulation CoatLevel Stearic Ethyl # (%) Acid* PVPS* Cellulose* Oligomer* 70418 1577.35 14.83 0 4.74 70430 10 84.49 7.14 0 4.74 70431 15 84.49 7.14 0 4.7470432 10 77.35 14.83 3.07 4.74 70433 12 77.35 14.83 3.07 4.74 70434 1581.2 15.56 0 0 70435 10 84.49 7.14 3.07 4.74 70437 12 84.49 7.14 0 4.7470438 12 77.35 14.83 0 4.74 70439 10 77.35 14.83 0 4.74 40740 10 84.497.14 0 4.74 *component presented as % of coating

The amount of HMTBa released from some of the formulations listed inTable 6 was tested using a gravimetric in vitro bag test. This test is asimulation of the rumen bag test described above in Example 2. For thein vitro bag test, coated particles were placed in a nylon bag which wasthen sealed with a zip-tie. Four separate bags were prepared for eachformulation to be tested. The initial weight of each bag containingcoated particles was measured. Each bag was place in a container filedwith a simulated rumen fluid that was buffered to a different pH level.The containers (with the bags) were closed and placed inside a 40° C.incubator oven, with constant shaking, for a period of 18 hours.

After 18 hours, samples were removed from each container and the amountof HMTBa was measured using an HPLC method. FIG. 5 shows the percent ofHMTBa released at the various pH levels during this 18 hour period. Allformulations showed limited release of HMTBa at pH 6.5 and 5.5, but goodrelease at pH 2.5.

Example 7: Time Course of In Vitro Release

The release of HMTBa from the formulations listed in Table 6 wasexamined at pH 2.5. Formulations were placed in a pH 2.5 solution,incubated at 40° C. (i.e., ruminant body temperature) and samples wereremoved at regular intervals over a 3 hour time period. The amount ofHMTBa was determined using an HPLC assay. FIG. 6 presents the kineticsof release. All formulations had a low release rate during the initial15 minutes and then the rates of release increased.

Example 8: Physical Resilience of the Coated Particles

The ability the coated particles to withstand mastication or mechanicalmanipulations was tested using an impact test. For this, a 24″ carbonsteel pipe was fitted with end caps and a cylindrical 95 gram stainlesssteel weight having an outer diameter that is about the same as theinner diameter of the pipe. The bottom of the pipe was capped, a sampleof the test formulation was placed in the bottom of the capped pipe, theweight was placed on top of the formulation, and the top end of the pipewas capped. The pipe was inverted so that the weight returned to whatwas the top of the pipe. The pipe was then brought back to startingposition and the weight fell to the bottom and hit the test formulation.This was counted as 1 impact. The process was repeated a certain numberof times (or weight impacts). After the pre-determined number of weightimpacts was completed, the end cap was removed and the test formulationwas collected, including all of the fines or powder. The recovered testformulation was mixed with a pH 5.5 solution and incubated for 2 hoursat 40° C. Samples were removed and analyzed by HPLC to determine theamount of active that was released into the solution.

The compositions of the coated particles that were tested are detailedin Table 7. The reference formulation was methionine granules coatedwith an amino-type polymer.

TABLE 7 Coated Particle Formulations Formulation Coat Level StearicEthyl # (%) Acid* PVPS* Cellulose* Oligomer* 75903 15.5 77.35 14.83 3.074.74 75904 17 77.35 14.83 3.07 4.74 75905 15.25 77.35 14.83 3.07 4.74*presented as % of coating

The results are presented in FIG. 7. The three test formulationsretained more than 50% of the active (i.e., HMTBa) even after 25 weightimpacts, whereas the reference formulation lost about 50% of the active(i.e., D,L-methionine) after 10 weight impacts.

Example 9: Comparative Simulated In Situ Release and Kinetics of Release

The three test formulations described above in Example 8 and thereference formulation were subjected to the in vitro bag testessentially as described above in Example 6. FIG. 8 shows that allformulations displayed release at pH 2.5.

The kinetics of release was examined in the three test formulationsdescribed above in Example 8 and the reference formulation essentiallyas described above in Example 7. The results are shown in FIG. 9. Thethree test formulations had higher rates of release at the earlier timepoints (i.e., 30 min, 1 hr, and 2 hr) than the reference formulation.

What is claimed is:
 1. A process for preparing a layer composition, theprocess comprising contacting a core comprising at least one bioactiveagent with a coating material comprising a first polymer comprisingrepeat units of Formula (I) and at least one additional agent chosenfrom a second polymer, a wax, a fatty acid, a fatty acid ester, or aflow agent, to form the layer composition comprising a layer over thecore, the repeat units of Formula (I) having the following structure:

wherein, R², R⁴, and R⁵ are independently hydrogen, hydrocarbyl, orsubstituted hydrocarbyl; R⁶ is hydrogen, hydrocarbyl, or substitutedhydrocarbyl; R⁷ is optional present, when present it is hydrogen,hydrocarbyl, or substituted hydrocarbyl; Z is sulfur, sulfone,sulfoxide, or selenium; n is an integer from 1 to 20; and m is aninteger >1.
 2. The process of claim 1, wherein R², R⁴, and R⁵ arehydrogen, R⁶ is C₁-C₆ alkyl, and n is from 1 to
 5. 3. The process ofclaim 2, wherein R⁶ is methyl, Z is sulfur, and n is
 2. 4. The processof claim 1, wherein the first polymer has an average molecular weight ofat least 500 Da.
 5. The process of claim 1, wherein the second polymeris a polymer of acrylates, acrylonitriles, aminoacrylates, alkylenesuccinates, alkylene oxalates, amides, amino acids, anhydrides,arylates, carbonates, celluloses, hydroxymethylcellulose,hydroxyproplycellulose, methylcellulose, carboxymethyl cellulose,ethylcellulose, caprolactone, cyanoacrylates, dihydropyrans, dioxanes,dioxanones, ether ether ketones, ethylene glycol, fumarates,hydroxyalkanoates, hydroxyesters, imides, ketals, lactides,methacrylates, methyl olefins, orthoesters, phosphazines, styrenes,terephthalates, trimethylene carbonate, urethanes, vinyl acetates, vinylesters, vinyl ketones, vinyl halides, or mixtures thereof.
 6. Theprocess of claim 1, wherein the at least one additional agent is apH-sensitive polymer, a cellulose polymer, a fatty acid, or a mixturethereof.
 7. The process of claim 6, wherein the pH-sensitive polymer ispoly-2-vinylpyridine-co-styrene, the cellulose polymer isethylcellulose, and the fatty acid is a C₁₂-C₃₀ fatty acid.
 8. Theprocess of claim 1, wherein the coating material further compriseswater, an organic solvent, or a mixture thereof.
 9. The process of claim1, wherein the coating material is applied by a fluid bed process, andthe layer over the core comprises from about 8% to about 12% by weightof the layer composition.
 10. The process of claim 1, wherein the atleast one bioactive agent is an essential oil, an amino acid or ananalogue of an amino acid, a vitamin, a mineral, an antioxidant, apigment, an enzyme, an organic acid, a poly unsaturated fatty acid, aprebiotic, a probiotic, a herb, a pharmaceutically active agent, or amixture thereof.
 11. The process of claim 10, wherein the at least onebioactive is an amino acid or an analogue of an amino acid.
 12. Theprocess of claim 11, wherein the at least one bioactive is a calciumsalt of 2-hydroxy-4-(methylthio)butanoic acid.
 13. The process of claim1, further comprising applying at least one additional layer on thelayer composition.
 14. A process for preparing an agglomeratedcomposition, the process comprising contacting at least one bioactiveagent, a first polymer comprising repeat units of Formula (I), and atleast one additional agent chosen from a second polymer, a wax, a fattyacid, a fatty acid ester, or a flow agent, to form the agglomeratedcomposition which comprises a plurality of bioactive agents embedded ina matrix, the repeat units of Formula (I) having the followingstructure:

wherein, R², R⁴, and R⁵ are independently hydrogen, hydrocarbyl, orsubstituted hydrocarbyl; R⁶ is hydrogen, hydrocarbyl, or substitutedhydrocarbyl; R⁷ is optional present, when present it is hydrogen,hydrocarbyl, or substituted hydrocarbyl; Z is sulfur, sulfone,sulfoxide, or selenium; n is an integer from 1 to 20; and m is aninteger >1.
 15. The process of claim 14, wherein R², R⁴, and R⁵ arehydrogen, R⁶ is C₁-C₆ alkyl, and n is from 1 to
 5. 16. The process ofclaim 15, wherein R⁶ is methyl, Z is sulfur, and n is
 2. 17. The processof claim 14, wherein the first polymer has an average molecular weightof at least 500 Da.
 18. The process of claim 14, wherein the secondpolymer is a polymer of acrylates, acrylonitriles, aminoacrylates,alkylene succinates, alkylene oxalates, amides, amino acids, anhydrides,arylates, carbonates, celluloses, hydroxymethylcellulose,hydroxyproplycellulose, methylcellulose, carboxymethyl cellulose,ethylcellulose, caprolactone, cyanoacrylates, dihydropyrans, dioxanes,dioxanones, ether ether ketones, ethylene glycol, fumarates,hydroxyalkanoates, hydroxyesters, imides, ketals, lactides,methacrylates, methyl olefins, orthoesters, phosphazines, styrenes,terephthalates, trimethylene carbonate, urethanes, vinyl acetates, vinylesters, vinyl ketones, vinyl halides, or mixtures thereof.
 19. Theprocess of claim 14, wherein the at least one additional agent is apH-sensitive polymer, a cellulose polymer, a fatty acid, a fatty acidester, or a mixture thereof.
 20. The process of claim 14, wherein the atleast one bioactive agent is an essential oil, an amino acid or ananalogue of an amino acid, a vitamin, a mineral, an antioxidant, apigment, an enzyme, an organic acid, a poly unsaturated fatty acid, aprebiotic, a probiotic, a herb, a pharmaceutically active agent, or amixture thereof.
 21. The process of claim 20, wherein the at least onebioactive is an amino acid or an analogue of an amino acid.
 22. Theprocess of claim 21, wherein the at least one bioactive is a calciumsalt of 2-hydroxy-4-(methylthio)butanoic acid.
 23. The process of claim14, further comprising applying at least one layer on the agglomeratedcomposition.